Search

What’s the difference between MSG and table salt? A chemist explains

<a href="https://theconversation.com/profiles/nathan-kilah-599082">Nathan Kilah</a>, <a href="https://theconversation.com/institutions/university-of-tasmania-888">University of Tasmania</a> It’s dinner time. You’ve worked hard to prepare a nutritious and tasty meal. But after taking your first bite you feel something is missing. Perhaps you should have added more salt? Pepper? Or maybe even something more exotic like monosodium glutamate, better known as MSG? There are many <a href="https://theconversation.com/explainer-what-are-e-numbers-and-should-you-avoid-them-in-your-diet-43908">food additives</a> used in both home cooking and commercial products. These ingredients improve the flavour, smell, texture, appearance and longevity of foods. Salt and MSG are two well-known food additives. Both contain sodium, but there are plenty of differences which you can use to your benefit. <h2>What is a salt?</h2> Salts are made of positively and negatively charged components called ions. Salts generally dissolve in water, and are brittle. The names of salts often feature a metal (positively charged) followed by a non-metal (negatively charged). The common kitchen ingredient we call “salt” is just one type of salt. To distinguish it from all other salts, we should more specifically refer to it as “table salt”. Chemically, it’s sodium chloride. <h2>Sodium chloride</h2> After the quick chemistry lesson above, we can see that table salt, sodium chloride, contains a positively charged sodium and a negatively charged chlorine. These charged components are arranged in crystals of salt in a regular repeating pattern. Each sodium ion is surrounded by six chloride ions and each chloride ion is surrounded by six sodium ions. This arrangement gives the crystal a “cubic” form. If you look closely at salt, you may see cube-shaped crystals. <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/617802/original/file-20240906-16-gk38c9.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" alt="" /></a><figcaption>The chemical structure of table salt forms a cube of sodium and chloride ions. <a class="source" href="https://www.shutterstock.com/image-vector/sodium-chloride-nacl-structure-ionic-crystal-2417242373">Sandip Neogi/Shutterstock</a></figcaption></figure> Sodium chloride is very abundant. It is found <a href="https://theconversation.com/i-have-always-wondered-why-is-the-sea-salty-83489">dissolved in Earth’s oceans</a>. Mineral deposits of salt, known as halite or rock salt, formed from the evaporation and crystallisation of ancient seas. Depending on the source, the salt may contain many other trace minerals that can even add colour to it, such as the pink-coloured Himalayan salt from Pakistan. Salt can also be fortified with <a href="https://www.who.int/publications/i/item/9789240053717">sodium iodide</a> as a public health measure. Describing the taste of salt is quite difficult without using the word “salty”. It’s a very common food additive, as it is so abundant and versatile. It is an essential ingredient for many traditional food preservation techniques for meats (pork and fish), vegetables (kimchi, sauerkraut and pickles), and dairy (cheese and butter). Salt is considered a universal flavouring agent. It can mask bitter flavours and bring out sweet, sour and <a href="https://theconversation.com/the-asian-roots-of-umami-the-fifth-taste-central-to-thanksgiving-fare-50699">umami</a> (savoury) ones. Despite popular depictions of <a href="https://theconversation.com/that-neat-and-tidy-map-of-tastes-on-the-tongue-you-learned-in-school-is-all-wrong-44217">taste maps</a>, there is no one place on the tongue where we taste salt. Other sodium salts can also give a “salty” taste, but the effect declines (and can even turn to bitter) with negatively charged components other than chloride. <h2>MSG or monosodium glutamate</h2> Monosodium glutamate is also a salt. The glutamate is the negatively charged form of glutamic acid, an amino acid that is found in nature as a building block of proteins. MSG, and more generally glutamates, are found in a wide range of foods including tomatoes, Parmesan cheese, soy sauce, dried seaweeds, Worcestershire sauce and protein-rich foods. All of these foods impart umami flavours, which are described as savoury or meaty. Commercial MSG is not extracted from the environment but produced by bacterial fermentation. Glucose is converted to glutamic acid, which is further processed by adding sodium hydroxide to form MSG (and water). MSG is sold as crystals, but they have a long, prismatic shape rather than the cubic form of sodium chloride. It’s worth tasting a few crystals of MSG directly to experience the native taste of umami. Despite decades of bad press and concern, <a href="https://theconversation.com/msg-is-back-is-the-idea-its-bad-for-us-just-a-myth-or-food-science-237871">MSG is considered safe</a> to consume in the concentrations typically found in or added to foods. Table salt and MSG both contain sodium, but at different percentages of the total weight: table salt has around 40% sodium, versus just 14% in MSG. You are also more likely to be routinely adding table salt to your food rather than MSG. Eating too much sodium is well known to be unhealthy. <a href="https://theconversation.com/this-salt-alternative-could-help-reduce-blood-pressure-so-why-are-so-few-people-using-it-221409">Potassium-enriched substitutes</a> have been suggested for a range of health benefits. <h2>A flavour enhancer</h2> The flavour of MSG can be elevated further by combining it with other food additives, known as sodium ribonucleotides. Japanese and Korean cooks figured this secret out long before chemists, as boiling dried fish and seaweed produces foundation stocks (dashi) containing a mix of naturally sourced glutamates and ribonucleotides. Ribonucleotides are classified as “generally considered as safe” by <a href="https://www.cfsanappsexternal.fda.gov/scripts/fdcc/index.cfm?set=FoodSubstances&id=DISODIUMINOSINATE&sort=Sortterm_ID&order=ASC&startrow=1&type=basic&search=disodium">food standards authorities</a>. Humans consume many grams of the natural equivalent in their diets. What can be more problematic are the carbohydrates- and fat-rich foods that have their flavours enhanced, which can potentially lead us to eat excessive calories. The combination of MSG and ribonucleotides produces a more-ish sensation. Next time you see a bag of potato chips or instant noodles, have a quick look to see if it contains both MSG (E621) and a ribonucleotide source (E627–E635). I personally keep a jar of MSG in my kitchen. A little goes a long way to elevate a soup, stew or sauce that isn’t quite tasting the way you want it to, but without adding too much extra sodium.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/237668/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/nathan-kilah-599082">Nathan Kilah</a>, Senior Lecturer in Chemistry, <a href="https://theconversation.com/institutions/university-of-tasmania-888">University of Tasmania</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/whats-the-difference-between-msg-and-table-salt-a-chemist-explains-237668">original article</a>.

Food & Wine

Airlines cancel flights after volcanic eruptions. An aviation expert explains why that’s a good thing

<a href="https://theconversation.com/profiles/patrick-murray-2027113">Patrick Murray</a>, <a href="https://theconversation.com/institutions/university-of-southern-queensland-1069">University of Southern Queensland</a> At least three airlines <a href="https://www.abc.net.au/news/2024-11-13/flights-to-and-from-bali-cancelled-due-to-volcanic-ash/104593698">cancelled flights between Australia and Bali</a> this week after a volcano eruption in eastern Indonesia spewed a vast plume of volcanic ash into the air. But while would-be holiday makers are naturally <a href="https://7news.com.au/sunrise/volcanic-eruption-in-indonesia-forces-airlines-to-cancel-flights-to-bali-stranding-frustrated-passengers-c-16732486">upset</a> at having their plans disrupted, it’s worth remembering it’s not safe to fly planes through volcanic ash. So, how do airlines decide it’s not safe to fly when a volcano erupts? And why is volcanic ash so dangerous for aircraft, anyway? <h2>What does volcanic ash do to a plane?</h2> Volcanic ash particles are very, very abrasive. They can cause permanent damage to windscreens in the aircraft and can even make windscreens look opaque – like someone has gone over them with sandpaper. Imagine getting spectacles and scraping them over and over with sandpaper – that’s what you’d see if you were sitting in the cockpit. Volcanic ash can also clog or damage external sensors, leading to erroneous readings, and can infiltrate an aircraft’s ventilation system. This can affect cabin air quality and lead to potential respiratory issues. But the main issue, in fact, is the impact volcanic ash has on engines. A jet engine works by drawing in air, compressing it, mixing it with fuel and igniting it. This creates high-pressure exhaust gases that are expelled backward, which pushes the engine (and the aircraft) forward. The correct balance of fuel and airflow is crucial. When you disrupt airflow, it can cause the engine to stall. Ash particles that get inside the engines will melt and build up, causing disruption of the airflow. This could cause the engine to “flame out” or stall. Volcanic ash has a lot of silica in it, so when it melts it turns into something similar to glass. It won’t melt unless exposed to very high temperatures – but inside a jet engine, you do get very high temperatures. There was a famous incident in 1982 where a <a href="https://theaviationgeekclub.com/the-story-of-british-airways-flight-9-the-boeing-747-that-lost-all-four-engines-due-to-volcanic-ash-yet-it-landed-safely/">British Airways Boeing 747 plane</a> was flying in the vicinity of Indonesia and lost all four engines after it encountered volcanic ash spewing from Java’s Mount Galunggung. Fortunately, the pilot was able to <a href="https://simpleflying.com/gallunggung-glider-the-story-of-british-airways-flight-9/">restart the engines and land safely</a>, although the pilots were unable to see through the front windscreens. <h2>How do airlines decide it’s not safe to fly when a volcano erupts?</h2> The decision is made by each airline’s operational staff. Each airline’s operational team would be looking at the situation in real time today and making the decision based on their risk assessment. Every airline has a process of risk management, which is required by Australia’s Civil Aviation Safety Authority. Different airlines may tackle risk management in slightly different ways; you might have some cancelling flights earlier than others. But, in broad terms, the more sophisticated airlines would come to similar conclusions and they are likely all communicating with each other. Mostly, they make the call based on the extent of the plume – how big the cloud of ash is and where it’s going, bearing in mind that winds vary with altitude. As you get stronger winds with altitude, the ash can drift quite far from the source. There is also a United Nations agency called the <a href="https://www.icao.int/Pages/default.aspx">International Civil Aviation Organization</a>, which issues guidance on volcanic ash hazards. Various meteorological agencies around the world work together and liaise with aviation authorities to spread the word quickly if there is an eruption. For airlines to resume flights, the ash needs to clear and there needs to be a low probability of further eruptions. <h2>Passenger safety is the priority</h2> The underpinning reason behind these flight cancellations is safety. If you lose engines and you can’t see out the window, the risk to passenger safety is obvious. Naturally, people are upset about their holiday plans being held up. But it’s actually in passengers’ best interests to not fly through volcanic ash.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/243576/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/patrick-murray-2027113">Patrick Murray</a>, Emeritus Professor of Aviation, <a href="https://theconversation.com/institutions/university-of-southern-queensland-1069">University of Southern Queensland</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/airlines-cancel-flights-after-volcanic-eruptions-an-aviation-expert-explains-why-thats-a-good-thing-243576">original article</a>.

Travel Trouble

Distraught bride explains why no one showed for her wedding

The heartbroken bride who went viral after no one showed up to her wedding has updated her followers on the events leading up to the big day. Kalina Marie, a bride from the US, went <a href="https://oversixty.co.nz/lifestyle/relationships/what-did-we-do-bride-shares-heartbroken-reaction-to-empty-wedding" target="_blank" rel="noopener">viral</a> after she took to TikTok to share the gut-wrenching video of the moment her and her new husband Shane stepped inside the lavishly decorated hall with their son, as they tried to come to terms with the fact that only a handful of people showed to celebrate with them. “FIVE PEOPLE SHOWED UP!!!!!!! Like, are you kidding me!?!? As you see in the video, we enter the venue. And no one is there," she wrote in the caption of the video before adding, “It just makes me think, like, why? What did we do? Am I that bad of a person?" Her video raked up millions of views with many people sharing words of encouragement, and thousands of people asking for an update on the situation. Hundreds of comments asked Kalina if she had heard from any of the invitees who didn't show up, wondering if they had provided her with a reason. In response to the comments, Kalina made another video to share some context with her followers. She first explained that and her husband, who have been together for nine years, got engaged in 2019 and weren’t able to have their wedding when they had intended to, due to the pandemic. In January this year, they announced they were finally tying the knot in October and for the past 10 months, Ms Marie said she has been “blabbing about it” all over Facebook. “I created a Facebook event and invited everyone I could and also sent out over 25 invitations to our elders and those not on social media to make sure they were included as well,” she said in a video. Ms Marie said she received notice from 40 who said they would be coming to the big day, so she planned for that number by setting up the venue accordingly and ensuring her mum had catered enough food. She also made sure to check in with everyone the week of to confirm their attendance, and said “at least 20 people” had gotten back to her saying they were coming, leaving her asking why those people chose not to show up at the last minute. “If I could answer that, I would tell you. And no, I haven’t really received a lot of messages explaining why people weren’t there or giving me excuses,” she said. However, the newlywed said she was actually grateful for this because it meant she could get a clear understanding of who actually cared about her and her husband. “We’ve been having to deal with the grief of deleting a lot of people out of our lives,” she admitted. “For the most part, we’ve done a lot of re-evaluating our lives and just spending a lot of time appreciating what we have and what we had.” To anyone who has had something similar happen to them, Ms Marie says: “I am truly very sorry as I wouldn’t wish this on my worst enemy.” The comments section of the video was again flooded with words of support and encouragement for the newlyweds, as one person wrote, “My heart aches for you,” while another called it “cruel” and “unbelievable.” Others emphasised that it was a powerful learning moment: “You really find out who your friends are when you have a wedding. Sorry, you went through this,” insisted one commenter. “The people who didn’t turn up you don’t need in your life,” another reassured. Image credits: TikTok

Relationships

How do heat protectants for hair work? A chemistry expert explains

<a href="https://theconversation.com/profiles/daniel-eldridge-1494633">Daniel Eldridge</a>, <a href="https://theconversation.com/institutions/swinburne-university-of-technology-767">Swinburne University of Technology</a> Heat can do amazing things to change your hairstyle. Whether you’re using a curling wand to get ringlets, a flat iron to straighten or a hair dryer to style, it’s primarily the heat from these tools that delivers results. This comes with casualties. While your hair is surprisingly tolerant to heat compared with many other parts of your body, it can still only withstand so much. Heat treatment hair appliances frequently operate at over 150°C, with some reportedly <a href="https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2019.00298/full#B13">reaching</a> <a href="https://www.researchgate.net/publication/289291195_Thermal_degradation_of_hair_I_Effect_of_curling_irons">over 200°C</a>. At these temperatures, your hair can end up fried. Many people use heat protectants, often in the form of sprays, to minimise the damage. So how do these protectants work? To answer that, I first have to explain exactly what heat does to your tresses on the molecular level. <h2>What heat does to your hair</h2> A large proportion of your hair is made up of proteins. There are attractive forces between these proteins, known as hydrogen bonds. These bonds play a big role in dictating the shape of your locks. When you heat up your hair, the total attraction of these hydrogen bonds become weaker, allowing you to more easily re-shape your hair. Then, when it cools back down, these attractions between the proteins are re-established, helping your hair hold its new look until the proteins rediscover their normal structure. The cuticle – the outermost protective layer of your hair – contains overlapping layers of cells that lose integrity when they’re heated, damaging this outer protective layer. Inside that outer layer is the cortex, which is rich in a protein called keratin. Many proteins don’t <a href="https://pubmed.ncbi.nlm.nih.gov/21635854/">hold up structurally</a> after intense heating. Think of cooking an egg – the change you see is a result of the heat altering the proteins in that egg, unravelling them into different shapes and sizes. It’s a <a href="https://library.scconline.org/v049n04/33">similar story</a> when it comes to heating your hair. The proteins in your hair are also susceptible to heat damage, reducing the overall strength and integrity of the hair. Heat can also affect substances called melanin and <a href="https://pubmed.ncbi.nlm.nih.gov/21443842/">tryptophan</a> in your hair, resulting in a change in pigmentation. Heat-damaged hair is <a href="https://pubmed.ncbi.nlm.nih.gov/21635854/">harder to brush</a>. The damage is even more devastating if you use heat styling tools such as <a href="https://labmuffin.com/why-you-should-never-straighten-or-curl-wet-hair/">curling irons or straighteners</a> to <a href="https://library.scconline.org/v062n01/23">heat wet hair</a>, as at the high treatment temperatures, the water soaked up by the fibres can violently evaporate. The result of this is succinctly described by science educator and cosmetic chemist Michelle Wong, also known as <a href="https://labmuffin.com/how-do-heat-protectant-hair-products-work/">Lab Muffin</a>. She notes if you heat wet hair this way, “steam will blast through your hair’s structure”. This steam bubbling or bursting through the hair can <a href="https://pubmed.ncbi.nlm.nih.gov/21443842/">cause substantial damage</a>. It’s worth noting hair dryers don’t concentrate heat in the same way as styling tools such as flat irons or curling wands, but you still need to move the hair dryer around constantly to avoid heat building up in one spot and causing damage. Once heat damage is done, regardless of whether it is severe or mild, the best remaining options are symptom management or a haircut. For all of these reasons, when you’re planning to heat treat your hair, protection is a good idea. <h2>How hair protectants work</h2> When you spray on a hair protectant, many possible key ingredients can go to work. They can have <a href="https://library.scconline.org/v062n01/15">daunting-looking names</a> like polyvinyl pyrrolidone, methacrylates, polyquaterniums, silicones and more. These materials are chosen because they readily stick onto your hair, creating a coating, a bit like this: <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=225&fit=crop&dpr=1 600w, https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=225&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=225&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=283&fit=crop&dpr=1 754w, https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=283&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/615002/original/file-20240822-16-beyt90.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=283&fit=crop&dpr=3 2262w" alt="A cartoon of coating attached to a strand of hair." /></a><figcaption>Hair protectant applies a coating to your hair. Author provided</figcaption></figure> This coating is a protective layer; it’s like putting an oven mitt on your hands before you handle a hot tray from the oven. To demonstrate, I created these by examining hair under a microscope before and after heat protectant was applied: <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=369&fit=crop&dpr=1 754w, https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=369&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/615001/original/file-20240822-16-s2ufqy.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=369&fit=crop&dpr=3 2262w" alt="These high magnification images of untreated hair, and hair sprayed with a heat treatment spray, show what a difference it can make." /></a><figcaption>These high magnification images of untreated hair, and hair sprayed with a heat treatment spray, show how the product coats your hair strands. Author provided</figcaption></figure> Just like an oven mitt, a hair protectant delays the heat penetration, results in less heat getting through, and helps spread out the effect of the heat, a bit like in this image: <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=233&fit=crop&dpr=1 600w, https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=233&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=233&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=293&fit=crop&dpr=1 754w, https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=293&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/615003/original/file-20240822-16-tf7xsj.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=293&fit=crop&dpr=3 2262w" alt="Cartoon demonstrating the difference between heating unprotected and protected hair" /></a><figcaption>Hair protectant can help spread out the effects of the heat. Author provided</figcaption></figure> <a href="https://library.scconline.org/v049n04/33">This helps</a> prevent moisture loss and damage to both the protective surface cell layer (the cuticle) and the protein structure of the hair cortex. For these barriers to work at their best, these heat-protecting layers need to remain bound to your hair. In other words, they stick on really well. For this reason, continued use can sometimes cause a <a href="https://link.springer.com/article/10.1007/s12221-010-0507-9">buildup</a> which can change the feel and weight of your hair. This buildup is not permanent and can be removed with washing. One final and important note: just like when you use a mitt for the oven, heat does still get through. The only way to prevent heat damage to your hair altogether is to not use heated styling tools.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/233206/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/daniel-eldridge-1494633">Daniel Eldridge</a>, Senior Lecturer in Chemistry, <a href="https://theconversation.com/institutions/swinburne-university-of-technology-767">Swinburne University of Technology</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/how-do-heat-protectants-for-hair-work-a-chemistry-expert-explains-233206">original article</a>.

Beauty & Style

Readers response: What's a pain you can't truly explain until you've endured it?

When it comes to experiencing pain, many of us are used to hearing people say "I know how you feel" while they're empathising with your suffering. However, there are some kinds of pain - either physical or emotional - that cannot be understood until you experience them yourself. We asked our readers what pain you can't truly explain until you've endured it yourself, and the response was overwhelming. Here's what they said. Anne Hare - Shingles! Absolutely excruciating. I seriously considered topping myself until I was finally prescribed Lyrica. Took five months to recover as misdiagnosed twice so antivirals prescribed too late. Have the shot! Karen Ambrose - Childbirth. 15.5 hours of agony. Annette Maree - Pain from a dying nerve in a tooth. Royce Jowett - The worst pain is always the one you are currently experiencing, especially as you get older and forgetful. Julia Santos - Hip pain is hard to explain how it affects your whole day. Even trying to sleep is an adventure. And sneezing while your hips are inflamed is always fun. Betty Weller Edwards - Gallbladder stones. I would rather go through labor for 12 hours than have 4 hours off gallbladder pain. Sandra Morris - The loss of your child. Kevin Chapman - Chronic arthritis. The pain is 24/7, it never goes away. Danny Bennett - Divorce. Patricia White - Dislocated shoulder. Jill Harker - A couple of bulging discs in my back! Linda Charlton - Clot in the lungs, couldn't breathe thought I was having a heart attack in my 30's. Other than that, definitely childbirth. George Dworcowyi - Back spasms after a 7 hour operation on my broken spine. Maxine Cuevas - Losing two adult children at separate times. Josephine Broughton - White tail spider bite. Shelley Woolley - Ruptured ovarian cysts. Image credits: Shutterstock

Body

What happens in an autopsy? A forensics expert explains

<a href="https://theconversation.com/profiles/hayley-green-1542041">Hayley Green</a>, <a href="https://theconversation.com/institutions/western-sydney-university-1092">Western Sydney University</a> Sometimes it’s unclear how or why a person died. A detailed examination of the body after death, known as an autopsy or postmortem, can help find answers. Despite what you may have seen on TV crime shows, most autopsies are minimally invasive; body often stays intact throughout a mostly observational procedure. Sometimes, though, a more extended investigation is needed. Through each step of the autopsy process, the dignity and respect of the deceased is prioritised by all involved. <h2>Not every death will result in an autopsy</h2> If someone dies from natural causes, there is no evidence of suspicious circumstances or there is a recent medical history, the death is certified by a doctor. The person is then taken into the care of a funeral service. But when questions about the death remain, specialist doctors, <a href="https://pathology.health.nsw.gov.au/articles/pride-of-workmanship-award-for-nepean-mortuary-technician/">technicians</a> and support staff might investigate further. Sometimes this involves an autopsy. <h2>Non-coronial and coronial autopsies</h2> Depending on the circumstances of death, there are two types of autopsies in Australia: non-coronial and coronial. A non-coronial autopsy is done when the cause of death is known but more information is needed. For example, the family may wish to know: <ul> <li> the extent of a known medical condition that led to the death </li> <li> how effective any treatments leading up to the time of death were, or </li> <li> if there’s evidence of a potential undiagnosed medical condition that may have contributed to the death. </li> </ul> Non-coronial autopsies are done in a hospital mortuary or a forensic pathology facility by an anatomical pathologist or forensic pathologist. An anatomical pathologist is a specialist in the detection and diagnosis of disease in organs and tissues (mainly in the living). A forensic pathologist takes part in medico-legal investigations and examines the body and its organs to look for disease or injury that may have caused death. A coronial autopsy happens when death is unexpected, violent, unnatural or the result of an accident. Deaths like these are classified as “reportable” deaths; by law they must be reported to the coroner, who is a magistrate of the court with legal training. These reports (typically prepared by the police), as well as the <a href="https://legislation.nsw.gov.au/view/pdf/asmade/act-2009-41">legislation</a> relevant to the state, assist the coroner to decide whether or not to order an autopsy. This order can be a minimally invasive external examination, an internal examination of a single body cavity or an invasive multiple cavity autopsy. Coronial autopsies are done in a <a href="https://www.abc.net.au/news/2019-05-27/australias-biggest-and-newest-morgue-in-sydneys-west/11142810">forensic pathology facility</a> by a <a href="https://pathology.health.nsw.gov.au/articles/a-video-profile-of-the-role-of-forensic-pathologist-at-nsw-health-pathology">forensic pathologist</a>. <h2>The first steps</h2> Someone who has died under “reportable” circumstances will be admitted to the forensic facility. The person’s identity will be established, where possible. If the coroner orders an autopsy, the body first undergoes a CT scan, which may be enough for the forensic pathologist to determine cause of death without further investigation. If not, the body will then be laid carefully on an examination table where any clothing and personal belongings are removed. The pathologist will then do an external examination, searching the body surface and recording any visible signs of cause of death or identifying marks. These might include tattoos or scars that can establish or confirm the identity of the deceased. Photographs of the body can be taken, and body fluids such as urine, blood and vitreous fluid from the eyes are sampled and tested for drugs, poisons or other substances. In many cases, the cause of death can be determined from the external examination alone and no further examination is necessary. Other times, more invasive methods are needed. <h2>Organ removal</h2> Evisceration is the important process of removing organs for the pathologist to examine in detail to help determine cause of death. The most common evisceration technique used in Australia is known as the <a href="https://www.pathologyoutlines.com/topic/forensicsautopsytechniques.html">Letulle method</a> (sometimes called the en masse method), where organs are removed in a single large block that starts at the tongue and throat and extends to the rectum. The first step of this process involves using a scalpel to make a large incision in the skin known commonly as the y-incision. This incision extends from behind each ear, or at times, the collar bones, to the mid line of the chest (just above the sternum). The incision will be extended through the centre of the chest towards the abdomen, stopping at the front of the pelvic bone. Skin, fat and muscle layers are pulled back to expose the neck structures, abdominal organs and the rib cage. The rib cage will then be cut on each side using shears to allow the front of the chest plate to be removed, revealing the heart and lungs. After an inspection of the positioning of the organs in the chest and abdomen, the bowel can be removed. Connections between organs and the body wall are separated and the organ block is then lifted from the body. Once out, the pathologist can do a detailed examination, weighing each organ individually. They will then dissect it to determine if there are any visible signs of disease or trauma that could have contributed to the cause of death. Tissue samples will be taken from each organ for histology (studying it under a microscope) to look for evidence of a cause of death. <h2>The brain</h2> A coroner may also request an examination of the brain. This involves an incision across the scalp within the hairline where possible, so the skin can be peeled back to expose the skull. The top of the skull will be removed using an oscillating saw to access the brain, which will then be removed (after separating it from the brainstem). The pathologist will look for signs of blood clots, trauma or disease. In some <a href="https://www.abc.net.au/news/2023-08-10/domestic-violence-repetitive-head-injury-cte-routine-screening/102682870">cases</a>, the coroner may make an order to keep the brain for a longer period of time for a more detailed and thorough examination. After the autopsy is over, the organs are returned to the abdominal cavity and all incisions are stitched closed. The body can then be released to the family and funeral arrangements made. An interim report on the cause of death is prepared for the coroner and made available to the family. This will be updated with a final determination on the cause of death after test results come back. Sometimes the cause of death will be listed as “unascertained”, meaning the cause of death could not be determined.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/232603/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/hayley-green-1542041">Hayley Green</a>, Senior Lecturer - Forensic Anthropology, <a href="https://theconversation.com/institutions/western-sydney-university-1092">Western Sydney University</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/what-happens-in-an-autopsy-a-forensics-expert-explains-232603">original article</a>.

Body

Yes, blue light from your phone can harm your skin. A dermatologist explains

<a href="https://theconversation.com/profiles/michael-freeman-223922">Michael Freeman</a>, <a href="https://theconversation.com/institutions/bond-university-863">Bond University</a> Social media is full of claims that everyday habits can harm your skin. It’s also full of recommendations or advertisements for products that can protect you. Now social media has blue light from our devices in its sights. So can scrolling on our phones really damage your skin? And will applying creams or lotions help? Here’s what the evidence says and what we should really be focusing on. <h2>Remind me, what actually is blue light?</h2> Blue light is part of the visible light spectrum. Sunlight is the strongest source. But our electronic devices – such as our phones, laptops and TVs – also emit it, albeit at levels <a href="https://melasmaclinic.com.au/wp-content/uploads/2024/01/Melasma-LEDS.pdf">100-1,000 times</a> lower. Seeing as we spend so much time using these devices, there has been some concern about the impact of blue light on our health, including <a href="https://theconversation.com/do-blue-light-glasses-really-work-can-they-reduce-eye-strain-or-help-me-sleep-213145">on our eyes and sleep</a>. Now, we’re learning more about the impact of blue light on our skin. <h2>How does blue light affect the skin?</h2> The evidence for blue light’s impact on skin is still emerging. But there are some interesting findings. 1. Blue light can increase pigmentation <a href="https://academic.oup.com/ced/article-abstract/46/5/934/6598472?redirectedFrom=fulltext&login=false">Studies</a> <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/srt.13401">suggest</a> exposure to blue light can stimulate production of melanin, the natural skin pigment that gives skin its colour. So too much blue light can potentially worsen hyperpigmentation – overproduction of melanin leading to dark spots on the skin – especially in people with darker skin. 2. Blue light can give you wrinkles Some research <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6280109/">suggests</a> blue light might damage collagen, a protein essential for skin structure, potentially accelerating the formation of wrinkles. A laboratory <a href="https://pubmed.ncbi.nlm.nih.gov/29399830/">study suggests</a> this can happen if you hold your device one centimetre from your skin for as little as an hour. However, for most people, if you hold your device more than 10cm away from your skin, that would reduce your exposure <a href="https://en.wikipedia.org/wiki/Inverse-square_law">100-fold</a>. So this is much less likely to be significant. 3. Blue light can disrupt your sleep, affecting your skin If the skin around your eyes looks dull or puffy, it’s easy to blame this directly on blue light. But as we know blue light affects sleep, what you’re probably seeing are some of the visible signs of sleep deprivation. We know blue light is particularly good at <a href="https://journals.physiology.org/doi/full/10.1152/japplphysiol.01413.2009?rss=1">suppressing</a> production of melatonin. This natural hormone normally signals to our bodies when it’s time for sleep and helps regulate our sleep-wake cycle. By suppressing melatonin, blue light exposure before bed disrupts this natural process, making it harder to fall asleep and potentially reducing the <a href="https://www.tandfonline.com/doi/abs/10.1080/07420528.2023.2173606">quality of your sleep</a>. The stimulating nature of screen content further disrupts sleep. Social media feeds, news articles, video games, or even work emails can keep our brains active and alert, hindering the transition into a sleep state. Long-term sleep problems can also <a href="https://academic.oup.com/ced/article-abstract/40/1/17/6621145?login=false">worsen</a> existing skin conditions, such as acne, eczema and rosacea. Sleep deprivation can elevate cortisol levels, a stress hormone that breaks down collagen, the protein responsible for skin’s firmness. Lack of sleep can also weaken the skin’s natural barrier, making it more susceptible to environmental damage and dryness. <h2>Can skincare protect me?</h2> The beauty industry has capitalised on concerns about blue light and offers a range of protective products such as mists, serums and lip glosses. From a practical perspective, probably only those with the more troublesome hyperpigmentation known as <a href="https://dermnetnz.org/topics/melasma">melasma</a> need to be concerned about blue light from devices. This condition requires the skin to be well protected from all visible light at all times. The only products that are totally effective are those that block all light, namely mineral-based suncreens or some cosmetics. If you can’t see the skin through them they are going to be effective. But there is a lack of rigorous testing for non-opaque products outside laboratories. This makes it difficult to assess if they work and if it’s worth adding them to your skincare routine. <h2>What can I do to minimise blue light then?</h2> Here are some simple steps you can take to minimise your exposure to blue light, especially at night when it can disrupt your sleep: <ul> <li> use the “night mode” setting on your device or use a blue-light filter app to reduce your exposure to blue light in the evening </li> <li> minimise screen time before bed and create a relaxing bedtime routine to avoid the types of sleep disturbances that can affect the health of your skin </li> <li> hold your phone or device away from your skin to minimise exposure to blue light </li> <li> use sunscreen. Mineral and physical sunscreens containing titanium dioxide and iron oxides offer broad protection, including from blue light. </li> </ul> <h2>In a nutshell</h2> Blue light exposure has been linked with some skin concerns, particularly pigmentation for people with darker skin. However, research is ongoing. While skincare to protect against blue light shows promise, more testing is needed to determine if it works. For now, prioritise good sun protection with a broad-spectrum sunscreen, which not only protects against UV, but also light.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/233335/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/michael-freeman-223922">Michael Freeman</a>, Associate Professor of Dermatology, <a href="https://theconversation.com/institutions/bond-university-863">Bond University</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/yes-blue-light-from-your-phone-can-harm-your-skin-a-dermatologist-explains-233335">original article</a>.

Body

Why do dogs have different coats? Experts explain – and give grooming tips for different types

<a href="https://theconversation.com/profiles/susan-hazel-402495">Susan Hazel</a>, <a href="https://theconversation.com/institutions/university-of-adelaide-1119">University of Adelaide</a> and <a href="https://theconversation.com/profiles/mia-cobb-15211">Mia Cobb</a>, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a> Dog hair comes in many varieties, from shaggy to short, curly to straight. If you live with a dog, you live with their hair – on your couch, in your clothes, it’s everywhere! Beyond colour, have you ever wondered what’s behind the differences in coat type? We actually know quite a lot about why dogs have different coats, and it comes down to their genes. <h2>What are the main coat types in dogs?</h2> The three main features of dog coats are how long the hairs are, whether they are curly or straight, and whether they have extra flourishes. The flourishes are called “furnishings”, and can include a hairy moustache and shaggy eyebrows. Combinations of these three features result in seven different coat types in dogs: short, wire, wire and curly, long, long with furnishings, curly, and curly with furnishings. We know from a <a href="https://www.science.org/doi/abs/10.1126/science.1177808">study of more than 1,000 dogs with varying coats</a> that differences in only three genes are responsible for this variety. The gene responsible for long hair (called FGF5) is <a href="https://learn.genetics.utah.edu/content/basics/patterns">recessive</a>, meaning dogs must have two copies of the mutated gene to have long hair. <a href="https://doi.org/10.1073/pnas.1402862111">In humans</a>, the same gene has been identified in families with excessively long eyelashes. Curly coats in dogs are related to a gene called <a href="https://www.pawprintgenetics.com/products/tests/details/173/">KRT71</a>, which affects keratin, a protein involved in hair formation. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2974189/">Mutations in this gene</a> in cats result in hairless (Sphynx) or curly-haired (Devon Rex) breeds. The gene responsible for furnishings (<a href="https://medlineplus.gov/genetics/gene/rspo2/">RSPO2</a>) is involved in establishing hair follicles. <a href="https://www.healthline.com/health/hair-follicle">Hair follicles</a> are small pockets in the skin that grow hair. Variations in these three genes could explain the coat type in most (but not all!) of the dogs tested. For example, the long coat of the Afghan hound is not explained by these three genes. Further study is needed to identify less common mutations and genes controlling the coat in these dogs. The earliest dog breeds would have been short-haired, as a result of the “wild-type” genes. Later changes would have arisen through mutation and deliberate selection <a href="https://theconversation.com/managing-mutations-of-a-species-the-evolution-of-dog-breeding-96635">through modern breeding practices</a>. If all three mutations are present, the dog has a long, curly coat with furnishings. An example is the Bichon Frisé. <h2>What else varies in dog coats?</h2> Dog coat types can also be single or double. In a double-coated breed such as a Labrador, there is a longer coarse layer of hairs and a softer and shorter undercoat. Wolves and ancestral dogs are single-coated, and the double coat is a result of a <a href="https://www.mdpi.com/2073-4425/10/5/323">mutation in chromosome 28</a>. In the Labrador, the mutation was probably selected for as they were bred to <a href="https://www.gov.nl.ca/releases/2023/exec/0525n07/">retrieve fishing nets in Canada</a>. The double coat is a great insulator and helps them to stay warm, even in icy water. <h2>Why does it matter what kind of coat a dog has?</h2> We know with climate change our world is going to get hotter. Dogs with a double coat are less able to tolerate heat stress, as their hair prevents heat loss. In a study of dogs <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/avj.13296">suffering heat-related illness</a>, most of the 15 breeds at higher risk had double coats. The death rate in these dogs was 23%. We can only imagine how it must feel going out on a 40 degree day wearing a thick fur coat. Dogs with a double coat shed more hair than dogs with a single coat. This means even short-haired breeds, like the Labrador retriever, can shed an astonishing amount of hair. If you can’t tolerate dog hair, then a dog with a double-coat may not suit you. When we think of wool we think of sheep, but in the past <a href="https://www.si.edu/stories/woolly-dog-mystery-unlocked">woolly dogs were kept for their wool</a> that was <a href="https://www.science.org/doi/10.1126/science.adi6549">woven by Indigenous groups</a> and used to make blankets. A dog’s coat also affects how much time and effort is needed for grooming. Dogs with long or curly hair with furnishings are likely to need more time invested in their care, or visits to a professional groomer. Designer dogs (cross-bred dogs often crossed with a poodle, such as groodles), are likely to be curly with furnishings. In a US study, people with designer dogs reported meeting their dogs’ maintenance and grooming requirements was <a href="https://www.mdpi.com/2076-2615/12/23/3247">much harder than they expected</a>. It’s not just bank balances and the time needed that can suffer. If people are unable to cope with the demands of grooming long-haired dogs, lack of grooming can cause welfare problems. A study of animal cruelty cases in New York found <a href="https://www.frontiersin.org/articles/10.3389/fvets.2022.827348/full">13% involved hair matting</a>, with some hair mats causing strangulation wounds and 93% of affected dogs having long hair. <h2>How can you prevent problems?</h2> If you have a curly- or long-haired breed of dog, it will help to train them to like being brushed from an early age. You can do this by counter-conditioning so they have a positive emotional response to being groomed, rather than feeling anxious. First show the brush or lightly brush them, then give them a treat. They learn to associate being brushed with something positive. If you take your dog to the groomer, it’s very important their first experience is positive. A scary or painful incident will make it much more difficult for future grooming. Is your dog difficult to groom or hard to get out of the car at the groomers? It’s likely grooming is scary for them. Consulting a dog trainer or animal behaviourist who focuses on positive training methods can help a lot. Keeping your dog well groomed, no matter their hair type, will keep them comfortable. More important than looking great, feeling good is an essential part of dogs living their best lives with us.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/232480/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/susan-hazel-402495">Susan Hazel</a>, Associate Professor, School of Animal and Veterinary Science, <a href="https://theconversation.com/institutions/university-of-adelaide-1119">University of Adelaide</a> and <a href="https://theconversation.com/profiles/mia-cobb-15211">Mia Cobb</a>, Research Fellow, Animal Welfare Science Centre, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/why-do-dogs-have-different-coats-experts-explain-and-give-grooming-tips-for-different-types-232480">original article</a>.

Family & Pets

Why do I poo in the morning? A gut expert explains

<div class="theconversation-article-body"> <a href="https://theconversation.com/profiles/vincent-ho-141549">Vincent Ho</a>, <a href="https://theconversation.com/institutions/western-sydney-university-1092">Western Sydney University</a> No, you’re not imagining it. People really are more likely to poo in the morning, shortly after breakfast. Researchers have actually studied this. But why mornings? What if you tend to poo later in the day? And is it worth training yourself to be a morning pooper? To understand what makes us poo when we do, we need to consider a range of factors including our body clock, gut muscles and what we have for breakfast. Here’s what the science says. <h2>So morning poos are real?</h2> In a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1379343/">UK study</a> from the early 1990s, researchers asked nearly 2,000 men and women in Bristol about their bowel habits. The most common time to poo was in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1379343/pdf/gut00573-0122.pdf">early morning</a>. The peak time was 7-8am for men and about an hour later for women. The researchers speculated that the earlier time for men was because they woke up earlier for work. About a decade later, <a href="https://pubmed.ncbi.nlm.nih.gov/16200717/">a Chinese study</a> found a similar pattern. Some 77% of the almost 2,500 participants said they did a poo in the morning. <h2>But why the morning?</h2> There are a few reasons. The first involves our <a href="https://theconversation.com/circadian-rhythm-nobel-what-they-discovered-and-why-it-matters-85072">circadian rhythm</a> – our 24-hour internal clock that helps regulate bodily processes, such as digestion. For healthy people, our internal clock means the muscular contractions in our colon follow <a href="https://pubmed.ncbi.nlm.nih.gov/19926812/">a distinct rhythm</a>. There’s minimal activity in the night. The deeper and more restful our sleep, the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4677652">fewer</a> of these muscle contractions we have. It’s one reason why we don’t tend to poo in our sleep. <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/597362/original/file-20240530-21-v2gvrq.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" alt="Diagram of digestive system including colon and rectum" /></a><figcaption>Your lower gut is a muscular tube that contracts more strongly at certain times of day. <a class="source" href="https://www.shutterstock.com/image-vector/illustration-healthcare-medical-education-drawing-chart-1984316789">Vectomart/Shutterstock</a></figcaption></figure> But there’s increasing activity during the day. Contractions in our colon are most active in the morning after waking up and after any meal. One particular type of colon contraction partly controlled by our internal clock are known as “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1411356/">mass movements</a>”. These are powerful contractions that push poo down to the rectum to prepare for the poo to be expelled from the body, but don’t always result in a bowel movement. In healthy people, these contractions occur a few times a day. They are more frequent in the morning than in the evening, and after meals. Breakfast is also a trigger for us to poo. When we eat and drink our stomach stretches, which triggers the “<a href="https://www.ncbi.nlm.nih.gov/books/NBK549888/">gastrocolic reflex</a>”. This reflex stimulates the colon to forcefully contract and can lead you to push existing poo in the colon out of the body. We know the gastrocolic reflex is strongest in the morning. So that explains why breakfast can be such a powerful trigger for a bowel motion. Then there’s our morning coffee. This is a very <a href="https://pubmed.ncbi.nlm.nih.gov/2338272/">powerful stimulant</a> of contractions in the sigmoid colon (the last part of the colon before the rectum) and of the rectum itself. This leads to a bowel motion. <h2>How important are morning poos?</h2> <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1846921/pdf/brmedj02601-0041.pdf">Large international</a> <a href="https://pubmed.ncbi.nlm.nih.gov/20205503/">surveys</a> show the vast majority of people will poo between three times a day and three times a week. This still leaves a lot of people who don’t have regular bowel habits, are regular but poo at different frequencies, or who don’t always poo in the morning. So if you’re healthy, it’s much more important that your bowel habits are comfortable and regular for you. Bowel motions do not have to occur once a day in the morning. Morning poos are also not a good thing for everyone. <a href="https://gut.bmj.com/content/61/Suppl_2/A318.1">Some people</a> with <a href="https://theconversation.com/explainer-what-is-irritable-bowel-syndrome-and-what-can-i-do-about-it-102579">irritable bowel syndrome</a> feel the urgent need to poo in the morning – often several times after getting up, during and after breakfast. This can be quite distressing. It appears this early-morning rush to poo is due to overstimulation of colon contractions in the morning. <h2>Can you train yourself to be regular?</h2> Yes, for example, to help treat constipation using the gastrocolic reflex. Children and elderly people with constipation can use the toilet immediately after eating breakfast <a href="https://www.ncbi.nlm.nih.gov/books/NBK549888/">to relieve symptoms</a>. And for adults with constipation, drinking coffee regularly can help stimulate the gut, particularly in the morning. A disturbed circadian rhythm can also lead to irregular bowel motions and people more likely to poo in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7147411/">evenings</a>. So better sleep habits can not only help people get a better night’s sleep, it can help them get into a more regular bowel routine. Regular physical activity and avoiding <a href="https://pubmed.ncbi.nlm.nih.gov/2787735/">sitting down a lot</a> are also important in <a href="https://pubmed.ncbi.nlm.nih.gov/16028436/">stimulating bowel movements</a>, particularly in people with constipation. We know <a href="https://theconversation.com/nervous-tummy-why-you-might-get-the-runs-before-a-first-date-106925">stress</a> can contribute to irregular bowel habits. So minimising stress and focusing on relaxation <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5193306/">can help</a> bowel habits become more regular. Fibre from fruits and vegetables also <a href="https://pubmed.ncbi.nlm.nih.gov/665565/">helps</a> make bowel motions more regular. Finally, ensuring <a href="https://theconversation.com/health-check-what-causes-constipation-114290">adequate hydration</a> helps minimise the chance of developing constipation, and helps make bowel motions more regular. <h2>Monitoring your bowel habits</h2> Most of us consider pooing in the morning to be regular. But there’s a wide variation in normal so don’t be concerned if your poos don’t follow this pattern. It’s more important your poos are comfortable and regular for you. If there’s a major change in the regularity of your bowel habits that’s concerning you, see your GP. The reason might be as simple as a change in diet or starting a new medication. But sometimes this can signify an important change in the health of your gut. So your GP may need to arrange further investigations, which could include blood tests or imaging.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/229624/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/vincent-ho-141549">Vincent Ho</a>, Associate Professor and clinical academic gastroenterologist, <a href="https://theconversation.com/institutions/western-sydney-university-1092">Western Sydney University</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/why-do-i-poo-in-the-morning-a-gut-expert-explains-229624">original article</a>. </div>

Body

Why do we love to see unlikely animal friendships? A psychology expert explains

<div class="theconversation-article-body"><a href="https://theconversation.com/profiles/shane-rogers-575838">Shane Rogers</a>, <a href="https://theconversation.com/institutions/edith-cowan-university-720">Edith Cowan University</a> The internet is awash with stories and videos of unlikely animal friendships, often with many millions of views. This content typically shows animals from different species showing affection to one another, signifying a bond or even a “friendship”. These relationships have been captured in people’s homes, such as with <a href="https://www.abc.net.au/news/2021-09-10/meet-unlikely-friends-peggy-the-dog-and-molly-the-magpie/100447022">Molly the magpie and Peggy the dog</a>, in zoos, <a href="https://www.abc.net.au/news/2016-03-04/bear-lion-and-tiger-make-an-affectionate,-gentle-family/7222462">such as with</a> Baloo the bear, Leo the lion and Shere Khan the tiger, and even <a href="https://www.youtube.com/watch?v=_BvB0182xag&t=2300s">in the wild</a>, such as one case of <a href="https://www.huffpost.com/entry/fox-cat-friendship_n_4268629">a fox and cat living together</a> in Turkey. <figure><iframe src="https://www.youtube.com/embed/fdxU6CpvUgg?wmode=transparent&start=19" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> A plethora of research on <a href="https://www.nature.com/articles/s41598-020-66407-w.pdf">primates</a>, <a href="https://blog.mybirdbuddy.com/post/can-birds-form-friendships">birds</a>, <a href="https://theconversation.com/the-social-lives-of-kangaroos-are-more-complex-than-we-thought-213770">kangaroos</a>, <a href="https://theconversation.com/male-dolphins-use-their-individual-names-to-build-a-complex-social-network-97780">dolphins</a>, <a href="https://www.mdpi.com/2076-2615/8/11/191">horses</a>, <a href="https://www.mdpi.com/2076-2615/12/1/126">cats</a> and <a href="https://www.nature.com/articles/s41598-022-05669-y">dogs</a> has shown many non-human animals can develop deep social bonds with their own kind. And while inter-species bonding hasn’t been studied to the same extent, videos like those mentioned above show animals from different species displaying the same affection to each other as they would to their own, such as through cuddling, playing and grooming. Why do we, as people, find these stories so enjoyable? Answering this question requires us to consider some of the nicer aspects of our own nature. <h2>When animals reflect us</h2> Witnessing animals get along well together isn’t just cute, it can also make us feel like we have things in common with other species, and feel more connected with the other life on the planet. <a href="https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2014.00976/full">Decades of research</a> reveals how feeling connected to nature fosters happiness in humans. <figure><iframe src="https://www.youtube.com/embed/PrJi-P61aLY?wmode=transparent&start=7" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> While the mechanisms behind inter-species bonding are not fully understood, <a href="https://www.frontiersin.org/articles/10.3389/fnbeh.2022.994504/full">one 2022 research review</a> suggests the mechanisms that operate in other animals’ brains during social interactions with their own are similar to those that operate in human brains. The researchers suggest that, due to the evolution of common brain mechanisms, animals engaged in social interaction may experience similar emotions to humans who engage with their own friends or loved ones. So while it’s very hard to know what this subjective social experience is like for other animals – after all, they can’t report it on a questionnaire – there’s no reason to think it isn’t similar to our own. <figure><iframe src="https://www.youtube.com/embed/ZVMsdz7aZpk?wmode=transparent&start=102" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> <h2>Humans like co-operation and pleasant surprises</h2> Humans have <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2022.0128">evolved to enjoy co-operation</a>, which might also help explain why we enjoy seeing co-operation between different animal species. <a href="https://www.abc.net.au/listen/programs/lifematters/competition-versus-cooperation:-which-human-instinct-is-stronge/10291360">Some scholars</a> suggest the human instinct for co-operation is even stronger than our instinct for competition. Another reason we may be drawn to unlikely animal friendships is that they are, in fact, so unlikely. These interactions are surprising, and research shows humans <a href="https://www.scientificamerican.com/article/neuroscientists-learn-why/">enjoy being surprised</a>. Our brain has <a href="https://www.imperial.ac.uk/news/239331/study-reveals-human-brains-have-evolved/">evolved to be incredibly efficient</a> at categorising, solving problems and learning. Part of the reason we’re so efficient is because we are motivated to seek new knowledge and question what we think we know. In other words, we’re motivated to be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4635443/">curious</a>. Inter-species friendships are indeed a very curious thing. They contradict the more common assumption and observation that different species stick with their own kind. We might think “cats eat birds, so they must not like each other”. So when we see <a href="https://www.youtube.com/watch?v=bGsN7jzp5DE">a cat and a bird</a> getting along like old pals, this challenges our concept of how the natural world works. <figure><iframe src="https://www.youtube.com/embed/bGsN7jzp5DE?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> Neuroscientists have documented that, when surprised, humans experience a release of brain chemicals responsible for making us <a href="https://www.scientificamerican.com/article/unexpected-brain-chemistry-is-behind-the-element-of-surprise/">more alert</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0896627320308539">sensitive to reward</a>. It is this neurochemical reaction that produces the “pleasantness” in the feeling of being pleasantly surprised. <h2>A desire for peace and harmony</h2> Perhaps another explanation for why humans are so intrigued by inter-species friendships is because they feed a human desire for peace and harmony. These connections may be symbolic of what many people yearn for: a world where differences can be put aside in favour of a peaceful co-existence. These friendships might even prompt us to imagine, consciously or subconsciously, a future in which we become more enlightened as a species. One could argue a key reason behind the success of the TV series <a href="https://www.youtube.com/watch?v=ANnFNfVuZeM">Star Trek</a> is its <a href="https://jacobin.com/2023/08/star-trek-solidarity-utopianism-technology-postcapitalism">optimistic take on the future of humanity</a>. Inter-species co-operation is a central theme of the show. Inter-species friendships may serve as a concrete example of breaking free of the “natural” way of being for a more peaceful way of being. And while it might only be a dream, it’s nice to watch cute animal videos that help us feel like this dream might be possible.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/230548/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <figure><iframe src="https://www.youtube.com/embed/_BvB0182xag?wmode=transparent&start=1880" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> <a href="https://theconversation.com/profiles/shane-rogers-575838">Shane Rogers</a>, Lecturer in Psychology, <a href="https://theconversation.com/institutions/edith-cowan-university-720">Edith Cowan University</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/why-do-we-love-to-see-unlikely-animal-friendships-a-psychology-expert-explains-230548">original article</a>. </div>

Family & Pets

How do airplanes fly? An aerospace engineer explains the physics of flight

<div class="theconversation-article-body"><a href="https://theconversation.com/profiles/craig-merrett-1509278">Craig Merrett</a>, <a href="https://theconversation.com/institutions/clarkson-university-4276">Clarkson University</a> Airplane flight is one of the most significant technological achievements of the 20th century. The <a href="https://airandspace.si.edu/explore/stories/wright-brothers">invention of the airplane</a> allows people to travel from one side of the planet to the other in less than a day, compared with weeks of travel by boat and train. Understanding precisely why airplanes fly is an ongoing challenge for <a href="https://www.clarkson.edu/people/craig-merrett">aerospace engineers, like me</a>, who study and design airplanes, rockets, satellites, helicopters and space capsules. Our job is to make sure that flying through the air or in space is safe and reliable, by using tools and ideas from science and mathematics, like computer simulations and experiments. Because of that work, flying in an airplane is <a href="https://usafacts.org/articles/is-flying-safer-than-driving/">the safest way to travel</a> – safer than cars, buses, trains or boats. But although aerospace engineers design aircraft that are stunningly sophisticated, you might be surprised to learn there are still some details about the physics of flight that we don’t fully understand. <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=381&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=381&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=381&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=479&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=479&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577439/original/file-20240222-28-v3tjb4.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=479&fit=crop&dpr=3 2262w" alt="A diagram of an airplane that shows the four forces of flight." /></a><figcaption>The forces of weight, thrust, drag and lift act on a plane to keep it aloft and moving. <a class="source" href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/airplane-cruise-balanced-forces/">NASA</a></figcaption></figure> <h2>May the force(s) be with you</h2> There are <a href="https://www.nasa.gov/stem-content/four-forces-of-flight/#:%7E">four forces</a> that aerospace engineers consider when designing an airplane: weight, thrust, drag and lift. Engineers use these forces to help design the shape of the airplane, the size of the wings, and figure out how many passengers the airplane can carry. For example, when an airplane takes off, the thrust must be greater than the drag, and the lift must be greater than the weight. If you watch an airplane take off, you’ll see the wings change shape using flaps from the back of the wings. The flaps help make more lift, but they also make more drag, so a powerful engine is necessary to create more thrust. When the airplane is high enough and is cruising to your destination, lift needs to balance the weight, and the thrust needs to balance the drag. So the pilot pulls the flaps in and can set the engine to produce less power. That said, let’s define what force means. According to <a href="https://ca.pbslearningmedia.org/resource/4079abf0-7a4b-4f49-80ad-c69cd06a80f9/newtons-second-law-of-motion/">Newton’s Second Law</a>, a force is a mass multiplied by an acceleration, or F = ma. A force that everyone encounters every day is <a href="https://spaceplace.nasa.gov/what-is-gravity/en/#:%7E">the force of gravity</a>, which keeps us on the ground. When you get weighed at the doctor’s office, they’re actually measuring the amount of force that your body applies to the scale. When your weight is given in pounds, that is a measure of force. While an airplane is flying, gravity is pulling the airplane down. That force is the weight of the airplane. But its engines push the airplane forward because they create <a href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/what-is-thrust/">a force called thrust</a>. The engines pull in air, which has mass, and quickly push that air out of the back of the engine – so there’s a mass multiplied by an acceleration. According to <a href="https://www.youtube.com/watch?v=a-wh3fJRdjo">Newton’s Third Law</a>, for every action there’s an equal and opposite reaction. When the air rushes out the back of the engines, there is a reaction force that pushes the airplane forward – that’s called thrust. As the airplane flies through the air, the shape of the airplane pushes air out of the way. Again, by Newton’s Third Law, this air pushes back, <a href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/what-is-drag/#:%7E">which leads to drag</a>. You can experience something similar to drag when swimming. Paddle through a pool, and your arms and feet provide thrust. Stop paddling, and you will keep moving forward because you have mass, but you will slow down. The reason that you slow down is that the water is pushing back on you – that’s drag. <h2>Understanding lift</h2> <a href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/what-is-lift/">Lift</a> is more complicated than the other forces of weight, thrust and drag. It’s created by the wings of an airplane, and the shape of the wing is critical; that shape is <a href="https://howthingsfly.si.edu/media/airfoil#:%7E">known as an airfoil</a>. Basically it means the top and bottom of the wing are curved, although the shapes of the curves can be different from each other. As air flows around the airfoil, <a href="https://www.youtube.com/watch?v=UO75jDwGCdQ">it creates pressure</a> – a force spread out over a large area. Lower pressure is created on the top of the airfoil compared to the pressure on the bottom. Or to look at it another way, air travels faster over the top of the airfoil than beneath. Understanding why the pressure and speeds are different on the top and the bottom is <a href="https://airandspace.si.edu/multimedia-gallery/lift-and-copjpg">critical to understand lift</a>. By improving our understanding of lift, engineers can design more fuel-efficient airplanes and give passengers more comfortable flights. <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579698/original/file-20240304-24-6df49v.jpg?ixlib=rb-4.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" alt="A diagram that shows how the airfoil of a plane works." /></a><figcaption>Note the airfoil, which is a specific wing shape that helps keep a plane in the air. <a class="source" href="https://www.gettyimages.com/detail/illustration/how-airplanes-fly-royalty-free-illustration/1401215523?phrase=airfoil+diagram&adppopup=true">Dimitrios Karamitros/iStock via Getty Images Plus</a></figcaption></figure> <h2>The conundrum</h2> The reason why air moves at different speeds around an airfoil remains mysterious, and <a href="https://www.scientificamerican.com/video/no-one-can-explain-why-planes-stay-in-the-air/">scientists are still investigating</a> this question. Aerospace engineers have measured these pressures on a wing in both wind tunnel experiments and during flight. We can create models of different wings to predict if they will fly well. We can also change lift by changing a wing’s shape to create airplanes that fly for long distances or fly very fast. Even though we still don’t fully know why lift happens, aerospace engineers work with mathematical equations that recreate the different speeds on the top and bottom of the airfoil. Those equations describe a process <a href="https://howthingsfly.si.edu/media/circulation-theory-lift">known as circulation</a>. Circulation provides aerospace engineers with a way to model what happens around a wing even if we do not completely understand why it happens. In other words, through the use of math and science, we are able to build airplanes that are safe and efficient, even if we don’t completely understand the process behind why it works. Ultimately, if aerospace engineers can figure out why the air flows at different speeds depending on which side of the wing it’s on, we can design airplanes that use less fuel and pollute less.  <a href="https://theconversation.com/profiles/craig-merrett-1509278">Craig Merrett</a>, Professor of Mechanical and Aerospace Engineering, <a href="https://theconversation.com/institutions/clarkson-university-4276">Clarkson University</a> Image credits: Shutterstock This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/how-do-airplanes-fly-an-aerospace-engineer-explains-the-physics-of-flight-222847">original article</a>. </div>

Travel Tips

Hospice nurse explains why we shouldn't be afraid to die

A hospice nurse has shared why we shouldn't be afraid to die, explaining all the ways in which our bodies "shut off" to make for a "peaceful" death. Julie McFadden, a nurse based in Los Angeles, has long been sharing videos and explanations about end of life care in an attempt to destigmatise the conversations and fear around death and dying. In her latest YouTube video, McFadden got candid with her followers as she confessed she isn't afraid to die and why no one else should be either. She went on to explain all the ways in which our bodies are supposed to "shut off" in our final moments, making for a "peaceful" and "natural" death. " "I'm not afraid of death and here's the science behind it, our body biologically helps us die, so here is what I've seen and learned as a hospice nurse over the years - our body is literally built to die," she said. The hospice nurse revealed that bodies began to slowly shut down in the six months leading up to death, explaining that a person nearing the end of their life would start "eating less, drinking less, and sleeping more." "Why is that happening? Because calcium levels in the body are going up and because calcium levels are going up the person is getting sleepier," Julie said. "Our brains have built in mechanisms to make us hungry and thirsty. Biologically, when the body knows it's getting towards the end of life those mechanisms shut off, so the person does not usually feel hungry and does not usually feel thirsty, which is helping the body slowly shut down." <iframe title="YouTube video player" src="https://www.youtube.com/embed/CJEkzA0gt6s?si=CIzcf3xchddKtf1D" width="560" height="315" frameborder="0" allowfullscreen="allowfullscreen"></iframe> She put minds at ease by debunking a common concern, saying that while certain diseases could make death more uncomfortable, dying in itself wasn't painful. "There are times when the disease that the person is experiencing can cause symptoms and it's more difficult because they're dying from a certain disease, but the actual process that the body is going through to help it die is actually helping that person," Julie added. "There have been many times as a hospice nurse that I have watched someone slowly die on hospice and I have not needed to give them any medication because their disease was not causing any symptoms - no pain, no shortness of breath, they were just more tired and weren't eating or drinking." "They still did all of the things any other person on hospice would be doing, like they slowly go unconscious, they slowly stop eating and drinking. I didn't have to give them any medications. They were perfectly comfortable and died a very peaceful death." Julie explained that death was even "comforting" in a way because when you're about to take your last breath, your body released endorphins, making you feel euphoric in your final moments. "The body slowly goes into something called ketosis, which releases endorphins. In that person's body those endorphins dull pain, dull nerves, and they also give that person a euphoric sense, so they feel good," she said. "There are many reasons why I don't fear death. Yes, I have had some pretty crazy spiritual experiences as a hospice nurse that led me to not fear death, but there are also biological, metabolical, and physiological things that happen in the body that truly, truly comforted me." She concluded, "Our bodies are built to die. The less we mess with that, the more peaceful it will be." Image credits: YouTube / Instagram

Caring

How much stress is too much? A psychiatrist explains the links between toxic stress and poor health − and how to get help

<a href="https://theconversation.com/profiles/lawson-r-wulsin-1493655">Lawson R. Wulsin</a>, <a href="https://theconversation.com/institutions/university-of-cincinnati-1717">University of Cincinnati </a> COVID-19 taught most people that the line between tolerable and toxic stress – defined as persistent demands that lead to disease – varies widely. But some people will age faster and die younger from toxic stressors than others. So how much stress is too much, and what can you do about it? I’m a <a href="https://researchdirectory.uc.edu/p/wulsinlr">psychiatrist specializing in psychosomatic medicine</a>, which is the study and treatment of people who have physical and mental illnesses. My research is focused on people who have psychological conditions and medical illnesses as well as those whose stress exacerbates their health issues. I’ve spent my career studying mind-body questions and training physicians to treat mental illness in primary care settings. My <a href="https://www.cambridge.org/core/books/toxic-stress/677FA62B741540DBDB53E2F0A52A74B1">forthcoming book</a> is titled “Toxic Stress: How Stress is Killing Us and What We Can Do About It.” A 2023 study of stress and aging over the life span – one of the first studies to confirm this piece of common wisdom – found that four measures of stress all speed up the pace of biological aging in midlife. It also found that persistent high stress ages people in a comparable way to the <a href="https://doi.org/10.1097/PSY.0000000000001197">effects of smoking and low socioeconomic status</a>, two well-established risk factors for accelerated aging. <figure><iframe src="https://www.youtube.com/embed/yiglpsqv5ik?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>Children with alcoholic or drug-addicted parents have a greater risk of developing toxic stress.</figcaption></figure> <h2>The difference between good stress and the toxic kind</h2> Good stress – a demand or challenge you readily cope with – is good for your health. In fact, the rhythm of these daily challenges, including feeding yourself, cleaning up messes, communicating with one another and carrying out your job, helps to regulate your stress response system and keep you fit. Toxic stress, on the other hand, wears down your stress response system in ways that have lasting effects, as psychiatrist and trauma expert Bessel van der Kolk explains in his bestselling book “<a href="https://www.penguinrandomhouse.com/books/313183/the-body-%20keeps-the-score-by-bessel-van-der-kolk-md/">The Body Keeps the Score</a>.” The earliest effects of toxic stress are often persistent symptoms such as headache, fatigue or abdominal pain that interfere with overall functioning. After months of initial symptoms, a full-blown illness with a life of its own – such as migraine headaches, asthma, diabetes or ulcerative colitis – may surface. When we are healthy, our stress response systems are like an orchestra of organs that miraculously tune themselves and play in unison without our conscious effort – a process called self-regulation. But when we are sick, some parts of this orchestra struggle to regulate themselves, which causes a cascade of stress-related dysregulation that contributes to other conditions. For instance, in the case of diabetes, the hormonal system struggles to regulate sugar. With obesity, the metabolic system has a difficult time regulating energy intake and consumption. With depression, the central nervous system develops an imbalance in its circuits and neurotransmitters that makes it difficult to regulate mood, thoughts and behaviors. <h2>‘Treating’ stress</h2> Though stress neuroscience in recent years has given researchers like me <a href="https://doi.org/10.1097/PSY.0000000000001051">new ways to measure and understand stress</a>, you may have noticed that in your doctor’s office, the management of stress isn’t typically part of your treatment plan. Most doctors don’t assess the contribution of stress to a patient’s common chronic diseases such as diabetes, heart disease and obesity, partly because stress is complicated to measure and partly because it is difficult to treat. In general, doctors don’t treat what they can’t measure. Stress neuroscience and epidemiology have also taught researchers recently that the chances of developing serious mental and physical illnesses in midlife rise dramatically when people are exposed to trauma or adverse events, especially during <a href="https://www.cdc.gov/violenceprevention/aces/ace-brfss.html">vulnerable periods such as childhood</a>. Over the past 40 years in the U.S., the alarming rise in <a href="https://www.cdc.gov/diabetes/health-equity/diabetes-by-the-numbers.html">rates of diabetes</a>, <a href="https://www.cdc.gov/nchs/data/hestat/obesity-child-17-18/overweight-obesity-child-H.pdf">obesity</a>, depression, PTSD, <a href="https://www.cdc.gov/nchs/products/databriefs/db433.htm">suicide</a> and addictions points to one contributing factor that these different illnesses share: toxic stress. Toxic stress increases the risk for the onset, progression, complications or early death from these illnesses. <h2>Suffering from toxic stress</h2> Because the definition of toxic stress varies from one person to another, it’s hard to know how many people struggle with it. One starting point is the fact that about 16% of adults report having been exposed to <a href="https://www.cdc.gov/violenceprevention/aces/fastfact.html">four or more adverse events in childhood</a>. This is the threshold for higher risk for illnesses in adulthood. Research dating back to before the COVID-19 pandemic also shows that about 19% of adults in the U.S. have <a href="https://doi.org/10.7249/TL221">four or more chronic illnesses</a>. If you have even one chronic illness, you can imagine how stressful four must be. And about 12% of the U.S. population <a href="https://blogs.worldbank.org/opendata/introducing-second-edition-world-banks-global-subnational-atlas-poverty">lives in poverty</a>, the epitome of a life in which demands exceed resources every day. For instance, if a person doesn’t know how they will get to work each day, or doesn’t have a way to fix a leaking water pipe or resolve a conflict with their partner, their stress response system can never rest. One or any combination of threats may keep them on high alert or shut them down in a way that prevents them from trying to cope at all. Add to these overlapping groups all those who struggle with harassing relationships, homelessness, captivity, severe loneliness, living in high-crime neighborhoods or working in or around noise or air pollution. It seems conservative to estimate that about 20% of people in the U.S. live with the effects of toxic stress. <figure><iframe src="https://www.youtube.com/embed/WuyPuH9ojCE?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>Exercise, meditation and a healthy diet help fight toxic stress.</figcaption></figure> <h2>Recognizing and managing stress and its associated conditions</h2> The first step to managing stress is to recognize it and talk to your primary care clinician about it. The clinician may do an assessment involving a <a href="https://doi.org/10.1097/PSY.0000000000001051">self-reported measure of stress</a>. The next step is treatment. Research shows that it is possible to retrain a dysregulated stress response system. This approach, <a href="https://lifestylemedicine.org/">called “lifestyle medicine</a>,” focuses on improving health outcomes through changing high-risk health behaviors and adopting daily habits that help the stress response system self-regulate. Adopting these lifestyle changes is not quick or easy, but it works. The <a href="https://www.cdc.gov/diabetes/prevention/index.html">National Diabetes Prevention Program</a>, the <a href="https://www.ornish.com/">Ornish “UnDo” heart disease program</a> and the <a href="https://www.ptsd.va.gov/understand_tx/tx_basics.asp">U.S. Department of Veterans Affairs PTSD program</a>, for example, all achieve a slowing or reversal of stress-related chronic conditions through weekly support groups and guided daily practice over six to nine months. These programs help teach people how to practice personal regimens of stress management, diet and exercise in ways that build and sustain their new habits. There is now strong evidence that it is possible to treat toxic stress in ways that improve health outcomes for people with stress-related conditions. The next steps include finding ways to expand the recognition of toxic stress and, for those affected, to expand access to these new and effective approaches to treatment.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/222245/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/lawson-r-wulsin-1493655">Lawson R. Wulsin</a>, Professor of Psychiatry and Family Medicine, <a href="https://theconversation.com/institutions/university-of-cincinnati-1717">University of Cincinnati</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/how-much-stress-is-too-much-a-psychiatrist-explains-the-links-between-toxic-stress-and-poor-health-and-how-to-get-help-222245">original article</a>.

Mind

Why do airlines charge so much for checked bags? This obscure rule helps explain why

<a href="https://theconversation.com/profiles/jay-l-zagorsky-152952">Jay L. Zagorsky</a>, <a href="https://theconversation.com/institutions/boston-university-898">Boston University</a> Five out of the six <a href="https://www.oag.com/blog/biggest-airlines-in-the-us">biggest U.S. airlines</a> have <a href="https://www.cnbc.com/2024/03/05/delta-is-the-latest-airline-to-raise-its-checked-bag-fee.html">raised their checked bag fees</a> since January 2024. Take American Airlines. In 2023, it cost US$30 to check a standard bag in with the airline; <a href="https://www.usatoday.com/story/travel/airline-news/2024/02/20/american-airlines-bag-fees-mileage-earning/72669245007/">today, as of March 2024, it costs $40</a> at a U.S. airport – a whopping 33% increase. As a <a href="https://www.bu.edu/questrom/">business school</a> <a href="https://www.bu.edu/questrom/profile/jay-zagorsky/">professor who studies travel</a>, I’m often asked why airlines alienate their customers with baggage fees instead of bundling all charges together. <a href="https://www.vox.com/2015/4/16/8431465/airlines-carry-on-bags">There are</a> <a href="https://www.usatoday.com/story/travel/columnist/2023/06/21/bag-fees-will-stay-a-while-cruising-altitude/70338849007/">many reasons</a>, but an important, often overlooked cause is buried in the U.S. tax code. <h2>A tax-law loophole</h2> Airlines pay the federal government <a href="https://www.ecfr.gov/current/title-26/chapter-I/subchapter-D/part-49/subpart-D">7.5% of the ticket price</a> when <a href="https://www.pwc.com/us/en/services/tax/library/aircraft-club-nov-2023-air-transport-excise-tax-rates-for-2024.html">flying people domestically, alongside other fees</a>. The airlines dislike these charges, with their <a href="https://www.airlines.org/dataset/government-imposed-taxes-on-air-transportation/">trade association arguing</a> that they boost the cost to the consumer of a typical air ticket by around one-fifth. However, the U.S. Code of Federal Regulations <a href="https://www.ecfr.gov/current/title-26/chapter-I/subchapter-D/part-49/subpart-D/section-49.4261-8">specifically excludes baggage</a> from the 7.5% transportation tax as long as “the charge is separable from the payment for the transportation of a person and is shown in the exact amount.” This means if an airline charges a combined $300 to fly you and a bag round-trip within the U.S., it owes $22.50 in tax. If the airline charges $220 to fly you plus separately charges $40 each way for the bag, then your total cost is the same — but the airline only owes the government $16.50 in taxes. Splitting out baggage charges saves the airline $6. Now $6 might not seem like much, but it can add up. Last year, passengers took <a href="https://www.transtats.bts.gov/Data_Elements.aspx?Data=1">more than 800 million trips on major airlines</a>. Even if only a fraction of them check their bags, that means large savings for the industry. How large? The government has <a href="https://www.bts.dot.gov/topics/airlines-and-airports/baggage-fees-airline-2023">tracked revenue from bag fees</a> for decades. In 2002, airlines charged passengers a total of $180 million to check bags, which worked out to around 33 cents per passenger. Today, as any flyer can attest, bag fees are a lot higher. Airlines collected over 40 times more money in bag fees last year than they did in 2002. When the full data is in for 2023, <a href="https://www.bts.dot.gov/baggage-fees">total bag fees</a> will likely top $7 billion, which is about $9 for the average domestic passenger. <a href="https://viewfromthewing.com/the-real-reason-airlines-charge-checked-bag-fees-and-its-not-what-you-think">By splitting out the cost of bags</a>, airlines avoided paying about half a billion dollars in taxes just last year. In the two decades since 2002, flyers paid a total of about $70 billion in bag fees. This means separately charging for bags saved airlines about $5 billion in taxes. <iframe id="88MYD" class="tc-infographic-datawrapper" style="border: none;" src="https://datawrapper.dwcdn.net/88MYD/2/" width="100%" height="400px" frameborder="0"></iframe> It seems clear to me that tax savings are one driver of the unbundling of baggage fees because of a quirk in the law. The U.S. government doesn’t apply the 7.5% tax to <a href="https://www.ecfr.gov/current/title-26/chapter-I/subchapter-D/part-49/subpart-D/section-49.4261-3">international flights that go more than 225 miles</a> beyond the nation’s borders. Instead, there are fixed <a href="https://www.airlines.org/dataset/government-imposed-taxes-on-air-transportation">international departure and arrival taxes</a>. This is why major airlines charge $35 to $40 <a href="https://www.aa.com/i18n/travel-info/baggage/checked-baggage-policy.jsp">for bags if you’re flying domestically</a>, but don’t charge a bag fee when you’re flying to Europe or Asia. <h2>Do travelers get anything for that money?</h2> This system raises an interesting question: Do baggage fees force airlines to be more careful with bags, since customers who pay more expect better service? To find out, I checked with the Bureau of Transportation Statistics, which has been <a href="https://www.bts.gov/content/mishandled-baggage-reports-filed-passengers-largest-us-air-carriersa">tracking lost luggage for decades</a>. For many years, it calculated the number of mishandled-baggage reports per thousand airline passengers. The government’s data showed mishandled bags peaked in 2007 with about seven reports of lost or damaged luggage for every thousand passengers. That means you could expect your luggage to go on a different trip than the one you are taking about once every 140 or so flights. By 2018, that estimate had fallen to once every 350 flights. In 2019, the government <a href="https://www.bts.gov/topics/airlines-and-airports/number-30a-technical-directive-mishandled-baggage-amended-effective-jan">changed how it tracks</a> mishandled bags, calculating figures based on the total number of bags checked, rather than the total number of passengers. The new data show about six bags per thousand checked get lost or damaged, which is less than 1% of checked bags. Unfortunately, the data doesn’t show improvement since 2019. Is there anything that you can do about higher bag fees? Complaining to politicians probably won’t help. In 2010, two senators <a href="https://www.nj.com/business/2010/04/us_senators_present_bill_to_ba.html">tried to ban bag fees</a>, and their bill went nowhere. Given that congressional action failed, there’s a simple way to avoid higher bag fees: <a href="https://www.cnn.com/travel/article/packing-expert-travel-world-handbag/index.html">travel light</a> and <a href="https://www.nytimes.com/2023/07/08/opinion/carry-on-packing-airlines-lost-luggage.html">don’t check any luggage</a>. It may sound tough not to have all your belongings when traveling, but it might be the best option as bag fees take off.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/225857/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/jay-l-zagorsky-152952">Jay L. Zagorsky</a>, Associate Professor of Markets, Public Policy and Law, <a href="https://theconversation.com/institutions/boston-university-898">Boston University</a> This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/why-do-airlines-charge-so-much-for-checked-bags-this-obscure-rule-helps-explain-why-225857">original article</a>.

Travel Trouble

Princess of Wales and King Charles: one in two people develop cancer during their lives – the diseases and treatments explained

<a href="https://theconversation.com/profiles/gavin-metcalf-1340598">Gavin Metcalf</a>, <a href="https://theconversation.com/institutions/anglia-ruskin-university-1887">Anglia Ruskin University</a> The Princess of Wales released a <a href="https://x.com/KensingtonRoyal/status/1771235267837321694?s=20">moving video message</a> on March 22 to address speculation about her health. In it, the future queen disclosed that she’d been <a href="https://www.bbc.co.uk/news/health-68641710">diagnosed with cancer</a> following tests conducted after she underwent major abdominal surgery at a clinic in London in January. Catherine explained that she was undergoing “preventative chemotherapy” – but emphasised that her surgery had been successful, and that she was “well” and “getting stronger every day”. The message was the <a href="https://www.theguardian.com/uk-news/2024/mar/22/princess-kate-cancer-royal-family-health-annus-horribilis">second announcement</a> of a royal family cancer diagnosis in recent weeks. On February 5, Buckingham Palace <a href="https://www.royal.uk/a-statement-from-buckingham-palace-5Feb24">published a statement</a> that King Charles III had been diagnosed with an undisclosed form of <a href="https://www.bbc.co.uk/news/uk-68208157">cancer, unrelated</a> to the treatment he had been receiving for an enlarged prostate. <figure><iframe src="https://www.youtube.com/embed/3xzKooCaRXU?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> The statement said that he had begun “regular treatments”. The king postponed all public-facing duties during his treatment, but <a href="https://www.bbc.co.uk/news/uk-68213383">reportedly continued</a> with his “constitutional role as head of state, including completing paperwork and holding private meetings”. Cancer is the <a href="https://www.who.int/news-room/fact-sheets/detail/cancer">leading cause of death</a> worldwide. <a href="https://www.nhs.uk/conditions/cancer/#:%7E:text=The%20cancerous%20cells%20can%20invade,of%20cancer%20during%20their%20lifetime.">One in two</a> people will develop some form of cancer in their lifetime – so the condition will affect almost every family. However, many cancers can be cured if, as appears to be the case with the king, the condition is <a href="https://www.bbc.co.uk/news/uk-68213383">detected early</a> and treated effectively. <h2>What is cancer?</h2> Our bodies are made up of more than 100 billion cells, and cancer typically starts with changes in a small group of cells – or even a single one. We have different cell types depending upon where in the body they are and the function that the cell has. The size, amount and function of each of these cells is normally tightly regulated by genes – groups of codes held within our DNA – that instruct cells how to grow and divide. However, changes (mutations) to DNA can alter the way cells grow and multiply – often forming a lump, or solid tumour. Cancers can also develop in blood cells, such as white blood cell cancer which is known as leukaemia. This type of cancer does not form solid tumours; instead, the cancer builds up in the blood or sometimes the marrow in the core of bones, where blood cells are produced. In all, there are <a href="https://www.cancerresearchuk.org/about-cancer/what-is-cancer/how-cancer-starts/types-of-cancer#:%7E:text=For%20example%2C%20nerves%20and%20muscles,of%20cell%20they%20start%20in.">more than 200</a> types of cancer, but all start with mutations in the DNA contained within each and every cell. <h2>What exactly are mutations?</h2> Think of your DNA as a big recipe book, and your genes as individual recipes for making different dishes. Mutations are smudges or missing words from this recipe that can result in key ingredients not being added into the mix. <figure><iframe src="https://www.youtube.com/embed/8BJ8_5Gyhg8?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> Regardless of the type of cancer or the cells from which it develops, mutations in our genes can result in a cell no longer understanding its instructions. These mutations can happen by chance when dividing, but can also be the result of lifestyle choices such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141049/">smoking</a>, <a href="https://www.ndph.ox.ac.uk/news/new-genetic-study-confirms-that-alcohol-is-a-direct-cause-of-cancer#:%7E:text=These%20mutations%20both%20disrupt%20the,aldehyde%20dehydrogenase%202%20(ALDH2).">drinking</a>, and <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/obesity/physical-activity-fact-sheet">inactivity</a>. Research has found that in order for a normal cell to turn into a cancerous cell, anywhere from <a href="https://www.sanger.ac.uk/news_item/1-10-mutations-are-needed-drive-cancer-scientists-find/">one to ten different mutations</a> are normally required. <h2>How is cancer treated?</h2> Treatment options for cancer depend on a variety of factors, including where your cancer is, how large it is, and whether it has spread to other parts of the body. The main treatments for cancer include surgery, chemotherapy, and radiotherapy. Chemotherapy uses drugs to target and kill cells that are rapidly dividing in our bodies. This approach is effective at targeting fast-growing cells in various cancers – but also has negative side effects. It also targets healthy cells that rapidly divide, such as hair and the cells lining our digestive system. This can lead to commonly reported <a href="https://www.nhs.uk/conditions/chemotherapy/side-effects/">side-effects</a> such as hair loss, nausea and diarrhoea. <a href="https://www.cancerresearchuk.org/about-cancer/treatment/chemotherapy?gad_source=1&gclid=Cj0KCQjw-_mvBhDwARIsAA-Q0Q6tyQxTuBzU7vVD7SHjQ5dF-fRdqnL7S74-k5LXyTqODydsrPfJVsoaAkgyEALw_wcB&gclsrc=aw.ds">Chemotherapy</a> can be used both preventatively – as in the case of the princess – and therapeutically. <figure><iframe src="https://www.youtube.com/embed/FkZn5u3MIiY?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> Preventative chemotherapy, also known as <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/adjuvant-therapy">adjuvant chemotherapy</a>, is given after surgery or other primary treatments to eliminate any remaining cancer cells in the body. It aims to reduce the risk of the cancer returning (known as recurrence). Therapeutic chemotherapy is used as a treatment option for cancer that has spread or is well established, such as advanced-stage cancers. <a href="https://www.cancerresearchuk.org/about-cancer/treatment/surgery/about">Surgery</a> involves the physical removal of cancerous tissues as well as nearby lymph nodes – small glands which act as filters in your body that cancers can spread through – to eliminate the tumour. Surgery is often used to remove localised cancers that haven’t spread throughout the body. <a href="https://www.cancerresearchuk.org/about-cancer/treatment/radiotherapy">Radiotherapy</a> uses high-energy radiation beams that are able to target specific areas where tumour cells are located to destroy or shrink the tumour. Radiotherapy can be applied externally or internally. Chemotherapy, surgery, and radiotherapy are often combined in cancer treatment to improve outcomes for patients. Thanks to developments in cancer research over the last 50 years, survival rates have improved greatly – although the rate of improvement has <a href="https://news.cancerresearchuk.org/2024/02/02/world-cancer-day-2024/#:%7E:text=Improvements%20in%20cancer%20survival%20have%20slowed%20in%20recent%20years&text=Survival%20increased%20three%20to%20five,consistently%20lags%20behind%20comparable%20countries.">slowed recently</a>. Cancer survival depends on various factors such as age – people under 40 have a <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/age">greater chance</a> of survival – overall health and fitness, as well as family history. <h2>What you should do</h2> Particular changes in your body or warning symptoms could indicate the presence of cancer. These include, but are not limited to: <ul> <li>Unexplained weight loss;</li> <li>Fatigue that doesn’t improve with rest;</li> <li>Changes in bowel or bladder habits;</li> <li>Persistent cough or coughing up blood;</li> <li>Difficulty swallowing;</li> <li>Persistent pain;</li> <li>Noticing lumps, such as in a breast or testicle.</li> </ul> The symptoms may not necessarily be the result of cancer. But it is important to get checked by a doctor if you notice anything out of the ordinary or have had persistent symptoms that don’t ease. Early detection and treatment can <a href="https://www.science.org/doi/full/10.1126/science.aay9040">significantly improve</a> outcomes for many types of cancer.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/226456/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/gavin-metcalf-1340598">Gavin Metcalf</a>, Cancer Biologist and Lecturer in Biomedical Science, <a href="https://theconversation.com/institutions/anglia-ruskin-university-1887">Anglia Ruskin University</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/princess-of-wales-and-king-charles-one-in-two-people-develop-cancer-during-their-lives-the-diseases-and-treatments-explained-226456">original article</a>.

Caring

Altitude sickness is typically mild but can sometimes turn very serious − a high-altitude medicine physician explains how to safely prepare

<a href="https://theconversation.com/profiles/brian-strickland-1506270">Brian Strickland</a>, <a href="https://theconversation.com/institutions/university-of-colorado-anschutz-medical-campus-4838">University of Colorado Anschutz Medical Campus</a> Equipped with the latest gear and a thirst for adventure, mountaineers embrace the perils that come with conquering the world’s highest peaks. Yet, even those who tread more cautiously at high altitude are not immune from the health hazards waiting in the thin air above. Altitude sickness, which most commonly refers to <a href="https://medlineplus.gov/ency/article/000133.htm">acute mountain sickness</a>, <a href="https://doi.org/10.1016/j.pcad.2010.02.003">presents a significant challenge</a> to those traveling to and adventuring in high-altitude destinations. Its symptoms can range from <a href="https://doi.org/10.1089/ham.2017.0164">mildly annoying to incapacitating</a> and, in some cases, may progress to more <a href="https://doi.org/10.1183/16000617.0096-2016">life-threatening illnesses</a>. While <a href="https://doi.org/10.18111/9789284424023">interest in high-altitude tourism is rapidly growing</a>, general awareness and understanding about the hazards of visiting these locations <a href="https://doi.org/10.1089/ham.2022.0083">remains low</a>. The more travelers know, the better they can prepare for and enjoy their journey. As an <a href="https://som.cuanschutz.edu/Profiles/Faculty/Profile/36740">emergency physician specializing in high-altitude illnesses</a>, I work to improve health care in remote and mountainous locations around the world. I’m invested in finding ways to allow people from all backgrounds to experience the magic of the mountains in an enjoyable and meaningful way. <h2>The science behind altitude sickness</h2> Altitude sickness is rare in locations lower than 8,200 feet (2,500 meters); however, <a href="https://www.ncbi.nlm.nih.gov/books/NBK430716/">it becomes very common</a> when ascending above this elevation. In fact, it affects about <a href="https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness">25% of visitors to the mountains of Colorado</a>, where I conduct most of my research. The risk rapidly increases with higher ascents. Above 9,800 feet (3,000 meters), up to <a href="https://www.ncbi.nlm.nih.gov/books/NBK430716/">75% of travelers</a> may develop symptoms. Symptoms of altitude sickness are usually mild and consist of <a href="https://doi.org/10.1089/ham.2017.0164">headache, dizziness, nausea, fatigue and insomnia</a>. They usually <a href="https://doi.org/10.1016/j.rceng.2019.12.009">resolve after one to two days</a>, as long as travelers stop their ascent, and the symptoms quickly resolve with descent. When travelers do not properly acclimatize, they can be susceptible to life-threatening altitude illnesses, such as <a href="https://doi.org/10.1016/j.resp.2007.05.002">high-altitude pulmonary edema</a> or <a href="https://doi.org/10.1089/1527029041352054">high-altitude cerebral edema</a>. These conditions are characterized by fluid accumulation within the tissues of the lungs and brain, respectively, and are the <a href="https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness">most severe forms of altitude sickness</a>. Altitude sickness symptoms are thought to be caused by <a href="https://doi.org/10.1093%2Fbjaceaccp%2Fmks047">increased pressure surrounding the brain</a>, which results from the failure of the body to acclimatize to higher elevations. As people enter into an environment with lower air pressure and, therefore, <a href="https://doi.org/10.1001/jamanetworkopen.2023.18036">lower oxygen content</a>, their <a href="https://doi.org/10.1093%2Fbjaceaccp%2Fmks047">breathing rate increases</a> in order to compensate. This causes an increase in the amount of <a href="https://doi.org/10.1016/s1357-2725(03)00050-5">oxygen in the blood as well as decreased CO₂ levels</a>, which then increases blood pH. As a result, the <a href="https://doi.org/10.1093%2Fbjaceaccp%2Fmks047">kidneys compensate</a> by removing a chemical called bicarbonate from the blood into the urine. This process makes people urinate more and helps correct the acid and alkaline content of the blood to a more normal level. <figure><iframe src="https://www.youtube.com/embed/iv1vQPIdX_k?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>Tips for preventing or reducing the risk of altitude sickness.</figcaption></figure> <h2>The importance of gradual ascent</h2> High-altitude medicine experts and other physicians <a href="https://doi.org/10.1016/s0140-6736(76)91677-9">have known for decades</a> that <a href="https://doi.org/10.1089/ham.2010.1006">taking time to slowly ascend is the best way</a> to prevent the development of altitude sickness. This strategy gives the body time to complete its natural physiologic responses to the changes in air pressure and oxygen content. In fact, spending just <a href="https://doi.org/10.1089/ham.2010.1006">one night at a moderate elevation</a>, such as Denver, Colorado, which is at 5,280 feet (1,600 meters), has been shown to <a href="https://doi.org/10.7326/0003-4819-118-8-199304150-00003">significantly reduce the likelihood of developing symptoms</a>. People who skip this step and travel directly to high elevations are <a href="https://doi.org/10.1093/jtm/taad011">up to four times more likely</a> to develop altitude sickness symptoms. When going to elevations greater than 11,000 feet, multiple days of acclimatization are necessary. Experts generally recommend ascending <a href="https://doi.org/10.1089/ham.2010.1006">no more than 1,500 feet per day</a> once the threshold of 8,200 feet of elevation has been crossed. Workers at high altitude, such as <a href="https://doi.org/10.1089/ham.2020.0004">porters in the Nepali Himalaya</a>, are at <a href="https://doi.org/10.1016/j.wem.2018.06.002">particular risk of altitude-related illness</a>. These workers often do not adhere to acclimatization recommendations in order to maximize earnings during tourist seasons; as a result, they are more likely to experience <a href="https://www.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness">severe forms of altitude sickness</a>. <h2>Effective medications</h2> For more than 40 years, <a href="https://doi.org/10.1056/nejm196810172791601">a medicine called acetazolamide</a> has been used to <a href="https://medlineplus.gov/druginfo/meds/a682756.html">prevent the development of altitude sickness</a> and to treat its symptoms. Acetazolamide is <a href="https://www.ncbi.nlm.nih.gov/books/NBK557838/">commonly used as a diuretic</a> and for the <a href="https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma">treatment of glaucoma</a>, a condition that causes increased pressure within the eye. If started <a href="https://doi.org/10.1378/chest.09-2445">two days prior</a> to going up to a high elevation, acetazolamide can <a href="https://doi.org/10.1378/chest.09-2445">prevent symptoms of acute illness</a> by speeding up the acclimatization process. Nonetheless, it does not negate the recommendations to ascend slowly, and it is <a href="https://doi.org/10.1016/j.wem.2019.04.006">routinely recommended only</a> when people cannot slowly ascend or for people who have a history of severe altitude sickness symptoms even with slow ascent. Other medications, including ibuprofen, have <a href="https://doi.org/10.1016/j.wem.2012.08.001">shown some effectiveness</a> in treating acute mountain sickness, although <a href="https://doi.org/10.1016/j.amjmed.2018.10.021">not as well as acetazolamide</a>. A <a href="https://pubmed.ncbi.nlm.nih.gov/2028586/">steroid medication called dexamethasone</a> is effective in both treating and preventing symptoms, but it does not improve acclimatization. It is <a href="https://doi.org/10.1016/j.wem.2019.04.006">recommended only when acetazolamide is not effective</a> or cannot be taken. Additionally, it is important to <a href="https://wwwnc.cdc.gov/travel/page/travel-to-high-altitudes">avoid alcohol during the first few days at higher altitudes</a>, as it impairs the body’s ability to acclimatize. <h2>Unproven therapies and remedies are common</h2> As high-altitude tourism becomes increasingly popular, multiple commercial products and remedies have emerged. Most of them are not effective or provide no evidence to suggest they work as advertised. Other options have mixed evidence, making them difficult to recommend. Medications such as <a href="https://doi.org/10.1089/ham.2007.1037">aspirin</a>, <a href="https://doi.org/10.1183/13993003.01355-2017">inhaled steroids</a> and <a href="https://doi.org/10.1089/ham.2011.0007">sildenafil</a> have been proposed as possible preventive agents for altitude sickness, but on the whole they have not been found to be effective. <a href="https://doi.org/10.1093/qjmed/hcp026">Supplements and antioxidants have no proven benefit</a> in preventing or treating altitude sickness symptoms. Both normal and high-altitude exercise are popular ways to prepare for high elevations, especially among athletes. However, beyond <a href="https://doi.org/10.1097/jes.0b013e31825eaa33">certain pre-acclimatization strategies</a>, such as brief sojourns to high altitude, <a href="https://doi.org/10.1016/j.tmaid.2013.12.002">physical fitness and training is of little benefit</a>. <a href="https://missouripoisoncenter.org/canned-oxygen-is-it-good-for-you">Canned oxygen</a> has also exploded in popularity with travelers. While <a href="https://doi.org/10.1016/0140-6736(90)93240-p">continuously administered medical oxygen</a> in a health care setting can alleviate altitude sickness symptoms, portable oxygen cans <a href="https://doi.org/10.1016/j.wem.2019.04.006">contain very little oxygen gas</a>, casting doubt on their effectiveness. Some high-altitude adventure travelers sleep in <a href="https://doi.org/10.2165/00007256-200131040-00002">specialized tents</a> that simulate increased elevation by lowering the quantity of available oxygen in ambient air. The lower oxygen levels within the tent are thought to accelerate the acclimatization process, but the tents aren’t able to decrease barometric pressure. This is an important part of the high-altitude environment that induces acclimatization. Without modifying ambient air pressure, these <a href="https://doi.org/10.1016/j.wem.2014.04.004">tents may take multiple weeks</a> to be effective. Natural medicines, such as <a href="https://doi.org/10.1580/08-weme-br-247.1">gingko</a> and <a href="https://doi.org/10.1186/s40794-019-0095-7">coca leaves</a>, are touted as natural altitude sickness treatments, but few studies have been done on them. The modest benefits and significant side effects of these options makes their use <a href="https://doi.org/10.1016/j.wem.2019.04.006">difficult to recommend</a>. <a href="https://pubmed.ncbi.nlm.nih.gov/8469948/">Staying hydrated</a> is very important at high altitudes due to fluid losses from increased urination, dry air and increased physical exertion. <a href="https://doi.org/10.1186%2Fs12889-018-6252-5">Dehydration symptoms</a> can also mimic those of altitude sickness. But there is <a href="https://doi.org/10.1580/1080-6032(2006)17%5B215:AMSIOF%5D2.0.CO;2">little evidence that consuming excessive amounts of water</a> can prevent or treat altitude sickness. The mountains have something for visitors of all interests and expertise and can offer truly life-changing experiences. While there are health risks associated with travel at higher elevations, these can be lessened by making basic preparations and taking time to slowly ascend.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/222057/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/brian-strickland-1506270">Brian Strickland</a>, Senior Instructor in Emergency Medicine, <a href="https://theconversation.com/institutions/university-of-colorado-anschutz-medical-campus-4838">University of Colorado Anschutz Medical Campus</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/altitude-sickness-is-typically-mild-but-can-sometimes-turn-very-serious-a-high-altitude-medicine-physician-explains-how-to-safely-prepare-222057">original article</a>.

Travel Trouble

Mothers’ dieting habits and self-talk have profound impact on daughters − 2 psychologists explain how to cultivate healthy behaviors and body image

<a href="https://theconversation.com/profiles/janet-j-boseovski-451496">Janet J. Boseovski</a>, <a href="https://theconversation.com/institutions/university-of-north-carolina-greensboro-2069">University of North Carolina – Greensboro</a> and <a href="https://theconversation.com/profiles/ashleigh-gallagher-1505989">Ashleigh Gallagher</a>, <a href="https://theconversation.com/institutions/university-of-north-carolina-greensboro-2069">University of North Carolina – Greensboro</a> Weight loss is one of the most common health and appearance-related goals. Women and <a href="https://www.cdc.gov/nchs/products/databriefs/db340.htm">teen girls</a> are <a href="https://www.cdc.gov/nchs/products/databriefs/db313.htm">especially likely to pursue dieting</a> to achieve weight loss goals even though a great deal of research shows that <a href="https://theconversation.com/what-thin-people-dont-understand-about-dieting-86604">dieting doesn’t work over the long term</a>. We are a <a href="https://www.duck-lab.com/people">developmental psychologist</a> and a <a href="https://psy.uncg.edu/directory/ashleigh-gallagher/">social psychologist</a> who together wrote a forthcoming book, “Beyond Body Positive: A Mother’s Evidence-Based Guide for Helping Girls Build a Healthy Body Image.” In the book, we address topics such as the effects of maternal dieting behaviors on daughters’ health and well-being. We provide information on how to build a foundation for healthy body image beginning in girlhood. <h2>Culturally defined body ideals</h2> Given the strong influence of social media and other cultural influences on body ideals, it’s understandable that so many people pursue diets aimed at weight loss. <a href="https://communityhealth.mayoclinic.org/featured-stories/tiktok-diets">TikTok</a>, YouTube, Instagram and celebrity websites feature slim influencers and “how-tos” for achieving those same results in no time. For example, women and teens are engaging in rigid and extreme forms of exercise such as 54D, a program to <a href="https://54d.com/">achieve body transformation in 54 days</a>, or the <a href="https://health.clevelandclinic.org/75-hard-challenge-and-rules">75 Hard Challenge</a>, which is to follow five strict rules for 75 days. For teens, these pursuits are likely fueled by trendy body preoccupations such as the desire for “<a href="https://www.nytimes.com/2024/02/06/well/move/tiktok-legging-legs-eating-disorders.html">legging legs</a>.” Women and teens have also been been inundated with recent messaging around <a href="https://theconversation.com/drugs-that-melt-away-pounds-still-present-more-questions-than-answers-but-ozempic-wegovy-and-mounjaro-could-be-key-tools-in-reducing-the-obesity-epidemic-205549">quick-fix weight loss drugs</a>, which come with a lot of caveats. Dieting and weight loss goals are highly individual, and when people are intensely self-focused, it is <a href="https://doi.org/10.1521/jscp.2000.19.1.70">possible to lose sight of the bigger picture</a>. Although women might wonder what the harm is in trying the latest diet, science shows that dieting behavior doesn’t just affect the dieter. In particular, for women who are mothers or who have other girls in their lives, these behaviors affect girls’ emerging body image and their health and well-being. <h2>The profound effect of maternal role models</h2> Research shows that mothers and maternal figures <a href="https://doi.org/10.1016/j.brat.2017.11.001">have a profound influence on their daughters’ body image</a>. The opportunity to influence girls’ body image comes far earlier than adolescence. In fact, research shows that these influences on body image <a href="https://www.teenvogue.com/story/how-toxic-diet-culture-is-passed-from-moms-to-daughters">begin very early in life</a> – <a href="https://doi.org/10.1016/bs.acdb.2016.10.006">during the preschool years</a>. Mothers may feel that they are being discreet about their dieting behavior, but little girls are watching and listening, and they are far more observant of us than many might think. For example, one study revealed that compared with daughters of nondieting women, 5-year-old girls whose mothers dieted <a href="https://doi.org/10.1016/S0002-8223(00)00339-4">were aware of the connection between dieting and thinness</a>. Mothers’ eating behavior does not just affect girls’ ideas about dieting, but also their daughters’ eating behavior. The amount of food that mothers eat <a href="https://doi.org/10.1016/j.appet.2018.04.018">predicts how much their daughters will eat</a>. In addition, daughters whose mothers are dieters are <a href="https://doi.org/10.1016/j.appet.2018.04.018">more likely to become dieters themselves</a> and are also <a href="https://doi.org/10.1016/j.eatbeh.2007.03.001">more likely to have a negative body image</a>. Negative body image is <a href="https://theconversation.com/mounting-research-documents-the-harmful-effects-of-social-media-use-on-mental-health-including-body-image-and-development-of-eating-disorders-206170">not a trivial matter</a>. It affects girls’ and women’s mental and physical well-being in a <a href="https://doi.org/10.1177/1359105317710815">host of ways</a> and <a href="https://doi.org/10.1016/j.brat.2011.06.009">can predict the emergence of eating disorders</a>. <h2>Avoiding ‘fat talk’</h2> What can moms do, then, to serve their daughters’ and their own health? They can focus on small steps. And although it is best to begin these efforts early in life – in girlhood – it is never too late to do so. For example, mothers can consider how they think about and talk about themselves around their daughters. Engaging in “fat talk” may inadvertently send their daughters the message that larger bodies are bad, <a href="https://doi.org/10.1016/j.bodyim.2020.07.004">contributing to weight bias</a> and negative self-image. Mothers’ fat talk also <a href="https://doi.org/10.1080/15267431.2021.1908294">predicts later body dissatisfaction in daughters</a>. And negative self-talk isn’t good for mothers, either; it is associated with <a href="https://doi.org/10.1177/1359105318781943">lower motivation and unhealthful eating</a>. Mothers can instead practice and model self-compassion, which involves treating oneself the way <a href="https://doi.org/10.1016/j.bodyim.2016.03.003">a loving friend might treat you</a>. In discussions about food and eating behavior, it is important to avoid moralizing certain kinds of food by labeling them as “good” or “bad,” as girls may extend these labels to their personal worth. For example, a young girl may feel that she is being “bad” if she eats dessert, if that is what she has learned from observing the women around her. In contrast, she may feel that she has to eat a salad to be “good.” Moms and other female role models can make sure that the dinner plate sends a healthy message to their daughters by showing instead that all foods can fit into a balanced diet when the time is right. Intuitive eating, which emphasizes paying attention to hunger and satiety and allows flexibility in eating behavior, is associated with <a href="https://doi.org/10.1007/s40519-020-00852-4">better physical and mental health in adolescence</a>. Another way that women and especially moms can buffer girls’ body image is by helping their daughters <a href="https://doi.org/10.1016/j.bodyim.2021.12.009">to develop media literacy</a> and to think critically about the nature and purpose of media. For example, moms can discuss the misrepresentation and distortion of bodies, such as the use of filters to enhance physical appearance, on social media. <h2>Focusing on healthful behaviors</h2> One way to begin to focus on health behaviors rather than dieting behaviors is to develop respect for the body and to <a href="https://theconversation.com/body-neutrality-what-it-is-and-how-it-can-help-lead-to-more-positive-body-image-191799">consider body neutrality</a>. In other words, prize body function rather than appearance and spend less time thinking about your body’s appearance. Accept that there are times when you may not feel great about your body, and that this is OK. To feel and look their best, mothers can aim to stick to a <a href="https://theconversation.com/whats-the-best-diet-for-healthy-sleep-a-nutritional-epidemiologist-explains-what-food-choices-will-help-you-get-more-restful-zs-219955">healthy sleep schedule</a>, manage their stress levels, <a href="https://theconversation.com/fiber-is-your-bodys-natural-guide-to-weight-management-rather-than-cutting-carbs-out-of-your-diet-eat-them-in-their-original-fiber-packaging-instead-205159">eat a varied diet</a> that includes all of the foods that they enjoy, and <a href="https://theconversation.com/the-runners-high-may-result-from-molecules-called-cannabinoids-the-bodys-own-version-of-thc-and-cbd-170796">move and exercise their bodies regularly</a> as lifelong practices, rather than engaging in quick-fix trends. Although many of these tips sound familiar, and perhaps even simple, they become effective when we recognize their importance and begin acting on them. Mothers can work toward modeling these behaviors and tailor each of them to their daughter’s developmental level. It’s never too early to start. <h2>Promoting healthy body image</h2> Science shows that several personal characteristics are associated with body image concerns among women. For example, research shows that women who are <a href="https://doi.org/10.1016/j.bodyim.2020.02.001">higher in neuroticism</a> <a href="https://doi.org/10.1186/2050-2974-1-2">and perfectionism</a>, <a href="https://doi.org/10.3389/fpsyg.2022.983534">lower in self-compassion</a> or <a href="https://doi.org/10.1016/j.bodyim.2013.08.001">lower in self-efficacy</a> are all more likely to struggle with negative body image. Personality is frequently defined as a person’s characteristic pattern of thoughts, feelings and behaviors. But if they wish, <a href="https://doi.org/10.1002/per.1945">mothers can change personality characteristics</a> that they feel aren’t serving them well. For example, perfectionist tendencies – such as setting unrealistic, inflexible goals – can be examined, challenged and replaced with more rational thoughts and behaviors. A woman who believes she must work out every day can practice being more flexible in her thinking. One who thinks of dessert as “cheating” can practice resisting moral judgments about food. Changing habitual ways of thinking, feeling and behaving certainly takes effort and time, but it is far more likely than diet trends to bring about sustainable, long-term change. And taking the first steps to modify even a few of these habits can positively affect daughters. In spite of all the noise from media and other cultural influences, mothers can feel empowered knowing that they have a significant influence on their daughters’ feelings about, and treatment of, their bodies. In this way, mothers’ modeling of healthier attitudes and behaviors is a sound investment – for both their own body image and that of the girls they love.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/221968/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/janet-j-boseovski-451496">Janet J. Boseovski</a>, Professor of Psychology, <a href="https://theconversation.com/institutions/university-of-north-carolina-greensboro-2069">University of North Carolina – Greensboro</a> and <a href="https://theconversation.com/profiles/ashleigh-gallagher-1505989">Ashleigh Gallagher</a>, Senior Lecturer, <a href="https://theconversation.com/institutions/university-of-north-carolina-greensboro-2069">University of North Carolina – Greensboro</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/mothers-dieting-habits-and-self-talk-have-profound-impact-on-daughters-2-psychologists-explain-how-to-cultivate-healthy-behaviors-and-body-image-221968">original article</a>.

Mind

How to make a perfect romcom – an expert explains the recipe for romance

<a href="https://theconversation.com/profiles/christina-wilkins-1454385">Christina Wilkins</a>, <a href="https://theconversation.com/institutions/university-of-birmingham-1138">University of Birmingham</a> Picture the scene: it’s a dreary weeknight evening, you’re tired from work, and you want to watch something that will pick you up. My guess is that some of you – perhaps more than would admit it – would pick a romantic comedy. Over the years the romcom has been designated as “chick flick”, dismissed at awards ceremonies (the best picture Oscar primarily goes to <a href="https://www.backstage.com/magazine/article/movie-genres-perform-best-oscars-2179/">drama films</a>) and frequently panned by critics. Yet, critics are not the only ones buying cinema tickets or watching streaming services. A 2013 <a href="https://archive.nytimes.com/economix.blogs.nytimes.com/2013/08/14/reviewing-the-movies-audiences-vs-critics/">article</a> from the New York Times found that the romcom was one of the genres most likely to divide audience and critical opinion. Like many other things that are classified as “women’s things”, the romcom is often spoken of as a “guilty pleasure”. Researchers such as Claire Mortimer, who <a href="https://www.routledge.com/Romantic-Comedy/Mortimer/p/book/9780415548632">writes about comedy</a> and women, argue that the dismissal is not just down to the genre’s <a href="https://stjohnslis.libguides.com/c.php?g=1277106&p=9378728">status as “women’s films”</a> but also because romcoms are genre films. Such films are often seen as repetitive – they rely on a number of tropes to be wheeled out again and again and we come to expect certain styles, stories and characters. Some films become key examples of a genre, a kind of “best of”, and form a template which the others either imitate or diverge from. That’s not to say that all romcoms are the same. But there’s a dominant form that we think of as being definitive, called the “neo-traditional romcom”. Tamar McDonald, a professor in film, <a href="https://books.google.co.uk/books?id=9Bk-mkvdPYcC&printsec=copyright&redir_esc=y#v=onepage&q&f=false">argues that</a> this is the main form of the genre now – one that “has no use for realism”. This can be seen in characters running through airports, the absurd lack of communication between love interests and the convenient mishaps. Without these elements though, the resolution wouldn’t be as sweet. <h2>The perfect romcom</h2> So what are the ingredients for a perfect romcom? Looking at the lists of the <a href="https://www.timeout.com/film/the-70-best-romcoms-of-all-time">best romcoms of all time</a> – which the internet <a href="https://www.vanityfair.com/hollywood/2018/08/best-romantic-comedies-list">isn’t short of</a> – we see similar tropes popping up repeatedly. One popular favourite, <a href="https://www.timeout.com/film/the-70-best-romcoms-of-all-time">When Harry Met Sally</a> (1989), features the “friends to lovers” storyline. This reoccurs in more recent films like <a href="https://www.youtube.com/watch?v=iHBcWHY9lN4">Always Be My Maybe</a> (2019). Within a romcom, there typically has to be miscommunication – and lots of it. Although a relationship can blossom steadily, often unknown to the characters themselves, romcoms usually feature a pivotal moment where one character is not understood by the person they want. This miscommunication is also underpinned by conflict. Leger Grindon, an expert <a href="https://www.google.co.uk/books/edition/The_Hollywood_Romantic_Comedy/okkZPTEnYqMC?hl=en&gbpv=1&dq=Leger+Grindon+rom+coms&printsec=frontcover%22%22">in romantic comedies</a>, breaks these kinds of conflict into three major fields: between parents and children, the two characters who are dating, or when someone has to choose between personal development and sacrifice. We’ve seen examples of all of three over the years. Children defying their parents’ wishes to be with someone they love is a common theme in the queer love story, like <a href="https://www.youtube.com/watch?v=h58HkQV1gHY">Happiest Season</a> (2020), but is also present in other films, like My <a href="https://www.youtube.com/watch?v=O2mecmDFE-Q">Big Fat Greek Wedding</a> (2002). <figure><iframe src="https://www.youtube.com/embed/O2mecmDFE-Q?wmode=transparent&start=19" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>My Big Fat Greek Wedding hinges on conflict between family and love.</figcaption></figure> Conflict between the needs of the love interests can be seen in <a href="https://www.youtube.com/watch?v=zZKAA5DRF4A">What Women Want</a> (2000). And the conflict between personal development and sacrifice has been a common theme of many recent Netflix romcoms such as <a href="https://www.youtube.com/watch?v=MX6wAGuIMCg">Hello, Goodbye and Everything in Between</a> (2022) or <a href="https://www.youtube.com/watch?v=km7gv28_uX0">The Holiday Calendar</a> (2019). In Hallmark Christmas films (their own sub-genre of the romcom) like <a href="https://www.youtube.com/watch?v=GWKYnKGN8OA">Just In Time for Christmas</a> (2015), women often have to choose between their career and their relationship, a common recurrence for the Christmas sub-genre especially. Romcoms can provide escapism, but at their heart the glue of the genre is finding connection through love and laughter. How realistic this is may be shifting, with more recent examples in film and television providing more cultural critique (see comedian Rose Matafeo’s brilliant <a href="https://www.youtube.com/watch?v=AtHC1VmrNXM">Starstruck</a> series, streaming on BBC Three for example). The parameters for the characters of these stories are also changing. Once predominantly white and straight, the genre is opening up to a range of different stories. Recent examples like <a href="https://theconversation.com/red-white-and-royal-blue-review-this-queer-romcom-puts-a-new-spin-on-the-us-and-uks-special-relationship-211533">Red, White, and Royal Blue</a> (2023) and <a href="https://www.imdb.com/title/tt9731598/">Bros</a> (2022) put gay male romance front and centre, while <a href="https://www.imdb.com/title/tt15893750/">Rye Lane</a> (2023) and <a href="https://theconversation.com/crazy-rich-asians-a-movie-and-a-movement-101568">Crazy Rich Asians</a> (2018) foreground non-white protagonists. Perhaps this is because – as <a href="https://www.routledge.com/Romantic-Comedy/Mortimer/p/book/9780415548632">Mortimer</a> argues – the genre is concerned with “perennial themes” of love and identity. In a moment where definitions and understandings of identity are shifting, the romcom provides an ideal place to think through these issues in a comforting way. Or perhaps we just need the optimism we associate with the genre at a time of war and economic crisis. Although there may be classics and new challengers emerging for the title of the best, the perfect romcom is one that shows that, despite all the challenges life may throw at us, there is sometimes a happy ending. <a href="https://theconversation.com/profiles/christina-wilkins-1454385">Christina Wilkins</a>, Lecturer in Film and Creative Writing, <a href="https://theconversation.com/institutions/university-of-birmingham-1138">University of Birmingham</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/how-to-make-a-perfect-romcom-an-expert-explains-the-recipe-for-romance-212487">original article</a>.

Movies

Does running water really trigger the urge to pee? Experts explain the brain-bladder connection

<a href="https://theconversation.com/profiles/james-overs-1458017">James Overs</a>, <a href="https://theconversation.com/institutions/swinburne-university-of-technology-767">Swinburne University of Technology</a>; <a href="https://theconversation.com/profiles/david-homewood-1458022">David Homewood</a>, <a href="https://theconversation.com/institutions/melbourne-health-950">Melbourne Health</a>; <a href="https://theconversation.com/profiles/helen-elizabeth-oconnell-ao-1458226">Helen Elizabeth O'Connell AO</a>, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a>, and <a href="https://theconversation.com/profiles/simon-robert-knowles-706104">Simon Robert Knowles</a>, <a href="https://theconversation.com/institutions/swinburne-university-of-technology-767">Swinburne University of Technology</a> We all know that feeling when nature calls – but what’s far less understood is the psychology behind it. Why, for example, do we get the urge to pee just before getting into the shower, or when we’re swimming? What brings on those “nervous wees” right before a date? Research suggests our brain and bladder are in constant communication with each other via a neural network called the <a href="https://www.einj.org/journal/view.php?doi=10.5213/inj.2346036.018">brain-bladder axis</a>. This complex web of circuitry is comprised of sensory neural activity, including the sympathetic and parasympathetic nervous systems. These neural connections allow information to be sent <a href="https://doi.org/10.3390/diagnostics12123119">back and forth</a> between the brain and bladder. The brain-bladder axis not only facilitates the act of peeing, but is also responsible for telling us we need to go in the first place. <h2>How do we know when we need to go?</h2> As the bladder fills with urine and expands, this activates special receptors detecting stretch in the nerve-rich lining of the bladder wall. This information is then relayed to the “periaqueductal gray” – a part of the brain in the brainstem which <a href="https://www.nature.com/articles/nrn2401">constantly monitors</a> the bladder’s filling status. <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" alt="" /></a><figcaption>The periaqueductal gray is a section of gray matter located in the midbrain section of the brainstem. <a class="source" href="https://en.wikipedia.org/wiki/Brainstem#/media/File:1311_Brain_Stem.jpg">Wikimedia/OpenStax</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></figcaption></figure> Once the bladder reaches a certain threshold (roughly 250-300ml of urine), another part of the brain called the “pontine micturition centre” is activated and signals that the bladder needs to be emptied. We, in turn, <a href="https://pubmed.ncbi.nlm.nih.gov/16254993/">register this</a> as that all-too-familiar feeling of fullness and pressure down below. Beyond this, however, a range of situations can trigger or exacerbate our need to pee, by increasing the production of urine and/or stimulating reflexes in the bladder. <h2>Peeing in the shower</h2> If you’ve ever felt the need to pee while in the shower (no judgement here) it may be due to the sight and sound of running water. In a 2015 study, <a href="https://doi.org/10.1371/journal.pone.0126798">researchers demonstrated</a> that males with urinary difficulties found it easier to initiate peeing when listening to the sound of running water being played on a smartphone. Symptoms of overactive bladder, including urgency (a sudden need to pee), have also been <a href="https://www.alliedacademies.org/articles/environmental-cues-to-urgency-and-incontinence-episodes-in-chinesepatients-with-overactive-urinary-bladder-syndrome.html">linked to</a> a range of environmental cues involving running water, including washing your hands and taking a shower. This is likely due to both physiology and psychology. Firstly, the sound of running water may have a relaxing physiological effect, increasing activity of the parasympathetic nervous system. This would relax the bladder muscles and prepare the bladder for emptying. At the same time, the sound of running water may also have a conditioned psychological effect. Due to the countless times in our lives where this sound has coincided with the actual act of peeing, it may trigger an instinctive reaction in us to urinate. This would happen in the same way <a href="https://www.simplypsychology.org/pavlov.html">Pavlov’s dog learnt</a>, through repeated pairing, to salivate when a bell was rung. <h2>Cheeky wee in the sea</h2> But it’s not just the sight or sound of running water that makes us want to pee. Immersion in cold water has been shown to cause a “cold shock response”, <a href="https://pubmed.ncbi.nlm.nih.gov/19945970">which activates</a> the sympathetic nervous system. This so-called “fight or flight” response drives up our blood pressure which, in turn, causes our kidneys to filter out more fluid from the bloodstream to stabilise our blood pressure, in a process called “<a href="https://link.springer.com/article/10.1007/BF00864230">immersion diuresis</a>”. When this happens, our bladder fills up faster than normal, triggering the urge to pee. Interestingly, immersion in very warm water (such as a relaxing bath) may also increase urine production. In this case, however, it’s due to activation of the parasympathetic nervous system. <a href="https://doi.org/10.1007/s004210050065">One study</a> demonstrated an increase in water temperature from 40℃ to 50℃ reduced the time it took for participants to start urinating. Similar to the effect of hearing running water, the authors of the study suggest being in warm water is calming for the body and activates the parasympathetic nervous system. This activation can result in the relaxation of the bladder and possibly the pelvic floor muscles, bringing on the urge to pee. <h2>The nervous wee</h2> We know stress and anxiety can cause bouts of nausea and butterflies in the tummy, but what about the bladder? Why do we feel a sudden and frequent urge to urinate at times of heightened stress, such as before a date or job interview? When a person becomes stressed or anxious, the body goes into fight-or-flight mode through the activation of the sympathetic nervous system. This triggers a cascade of physiological changes designed to prepare the body to face a perceived threat. As part of this response, the muscles surrounding the bladder may contract, leading to a more urgent and frequent need to pee. Also, as is the case during immersion diuresis, the increase in blood pressure associated with the stress response may <a href="https://doi.org/10.1172/JCI102496">stimulate</a> the kidneys to produce more urine. <h2>Some final thoughts</h2> We all pee (most of us several times a day). Yet <a href="https://doi.org/10.5489/cuaj.1150">research has shown</a> about 75% of adults know little about how this process actually works – and even less about the brain-bladdder axis and its role in urination. <a href="https://www.continence.org.au/about-us/our-work/key-statistics-incontinence#:%7E:text=Urinary%20incontinence%20affects%20up%20to,38%25%20of%20Australian%20women1.">Most Australians</a> will experience urinary difficulties at some point in their lives, so if you ever have concerns about your urinary health, it’s extremely important to consult a healthcare professional. And should you ever find yourself unable to pee, perhaps the sight or sound of running water, a relaxing bath or a nice swim will help with getting that stream to flow.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/210808/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/james-overs-1458017">James Overs</a>, Research Assistant, <a href="https://theconversation.com/institutions/swinburne-university-of-technology-767">Swinburne University of Technology</a>; <a href="https://theconversation.com/profiles/david-homewood-1458022">David Homewood</a>, Urology Research Registrar, Western Health, <a href="https://theconversation.com/institutions/melbourne-health-950">Melbourne Health</a>; <a href="https://theconversation.com/profiles/helen-elizabeth-oconnell-ao-1458226">Helen Elizabeth O'Connell AO</a>, Professor, University of Melbourne, Department of Surgery. President Urological Society Australia and New Zealand, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a>, and <a href="https://theconversation.com/profiles/simon-robert-knowles-706104">Simon Robert Knowles</a>, Associate Professor and Clinical Psychologist, <a href="https://theconversation.com/institutions/swinburne-university-of-technology-767">Swinburne University of Technology</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/does-running-water-really-trigger-the-urge-to-pee-experts-explain-the-brain-bladder-connection-210808">original article</a>.

Mind

If anxiety is in my brain, why is my heart pounding? A psychiatrist explains the neuroscience and physiology of fear

<a href="https://theconversation.com/profiles/arash-javanbakht-416594">Arash Javanbakht</a>, <a href="https://theconversation.com/institutions/wayne-state-university-989">Wayne State University</a> Heart in your throat. Butterflies in your stomach. Bad gut feeling. These are all phrases many people use to describe fear and anxiety. You have likely felt anxiety inside your chest or stomach, and your brain usually doesn’t hurt when you’re scared. Many cultures tie cowardice and bravery more <a href="https://afosa.org/the-meaning-of-heart-qalb-in-quran/">to the heart</a> <a href="https://byustudies.byu.edu/article/bowels-of-mercy/">or the guts</a> than to the brain. But science has traditionally seen the brain as the birthplace and processing site of fear and anxiety. Then why and how do you feel these emotions in other parts of your body? I am a <a href="https://scholar.google.com/citations?user=UDytFmIAAAAJ&hl=en">psychiatrist and neuroscientist</a> who researches and treats fear and anxiety. In my book “<a href="https://rowman.com/ISBN/9781538170380/Afraid-Understanding-the-Purpose-of-Fear-and-Harnessing-the-Power-of-Anxiety">Afraid,</a>” I explain how fear works in the brain and the body and what too much anxiety does to the body. Research confirms that while emotions do originate in your brain, it’s your body that carries out the orders. <h2>Fear and the brain</h2> While your brain evolved to save you from a falling rock or speeding predator, the anxieties of modern life are often a lot more abstract. Fifty-thousand years ago, being rejected by your tribe could mean death, but not doing a great job on a public speech at school or at work doesn’t have the same consequences. Your brain, however, <a href="https://doi.org/10.1006/nimg.2002.1179">might not know the difference</a>. There are a few key areas of the brain that are heavily involved in processing fear. When you perceive something as dangerous, whether it’s a gun pointed at you or a group of people looking unhappily at you, these sensory inputs are first relayed to <a href="https://doi.org/10.1038%2Fnpp.2009.121">the amygdala</a>. This small, almond-shaped area of the brain located near your ears detects salience, or the emotional relevance of a situation and how to react to it. When you see something, it determines whether you should eat it, attack it, run away from it or have sex with it. <a href="https://theconversation.com/the-science-of-fright-why-we-love-to-be-scared-85885">Threat detection</a> is a vital part of this process, and it has to be fast. Early humans did not have much time to think when a lion was lunging toward them. They had to act quickly. For this reason, the amygdala evolved to bypass brain areas involved in logical thinking and can directly engage physical responses. For example, seeing an angry face on a computer screen can immediately trigger a <a href="https://doi.org/10.1006/nimg.2002.1179">detectable response from the amygdala</a> without the viewer even being aware of this reaction. <figure><iframe src="https://www.youtube.com/embed/xoU9tw6Jgyw?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>In response to a looming threat, mammals often fight, flee or freeze.</figcaption></figure> <a href="https://doi.org/10.1038/npp.2009.83">The hippocampus</a> is near and tightly connected to the amygdala. It’s involved in memorizing what is safe and what is dangerous, especially in relation to the environment – it puts fear in context. For example, seeing an angry lion in the zoo and in the Sahara both trigger a fear response in the amygdala. But the hippocampus steps in and blocks this response when you’re at the zoo because you aren’t in danger. The <a href="https://doi.org/10.1176/appi.ajp.2016.16030353">prefrontal cortex</a>, located above your eyes, is mostly involved in the cognitive and social aspects of fear processing. For example, you might be scared of a snake until you read a sign that the snake is nonpoisonous or the owner tells you it’s their friendly pet. Although the prefrontal cortex is usually seen as the part of the brain that regulates emotions, it can also teach you fear based on your social environment. For example, you might feel neutral about a meeting with your boss but immediately feel nervous when a colleague tells you about rumors of layoffs. Many <a href="https://theconversation.com/trump-the-politics-of-fear-and-racism-how-our-brains-can-be-manipulated-to-tribalism-139811">prejudices like racism</a> are rooted in learning fear through tribalism. <h2>Fear and the rest of the body</h2> If your brain decides that a fear response is justified in a particular situation, it activates a <a href="https://doi.org/10.1093/med/9780190259440.003.0019">cascade of neuronal and hormonal pathways</a> to prepare you for immediate action. Some of the fight-or-flight response – like heightened attention and threat detection – takes place in the brain. But the body is where most of the action happens. Several pathways prepare different body systems for intense physical action. The <a href="https://doi.org/10.3389/fnins.2014.00043">motor cortex</a> of the brain sends rapid signals to your muscles to prepare them for quick and forceful movements. These include muscles in the chest and stomach that help protect vital organs in those areas. That might contribute to a feeling of tightness in your chest and stomach in stressful conditions. <figure><iframe src="https://www.youtube.com/embed/0IDgBlCHVsA?wmode=transparent&start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>Your sympathetic nervous system is involved in regulating stress.</figcaption></figure> The <a href="https://www.ncbi.nlm.nih.gov/books/NBK542195/">sympathetic nervous system</a> is the gas pedal that speeds up the systems involved in fight or flight. Sympathetic neurons are spread throughout the body and are especially dense in places like the heart, lungs and intestines. These neurons trigger the adrenal gland to release hormones like adrenaline that travel through the blood to reach those organs and increase the rate at which they undergo the fear response. To assure sufficient blood supply to your muscles when they’re in high demand, signals from the sympathetic nervous system increase the rate your heart beats and the force with which it contracts. You feel both increased heart rate and contraction force in your chest, which is why you may connect the feeling of intense emotions to your heart. In your lungs, signals from the sympathetic nervous system dilate airways and often increase your breathing rate and depth. Sometimes this results in a feeling of <a href="https://theconversation.com/pain-and-anxiety-are-linked-to-breathing-in-mouse-brains-suggesting-a-potential-target-to-prevent-opioid-overdose-deaths-174187">shortness of breath</a>. As digestion is the last priority during a fight-or-flight situation, sympathetic activation slows down your gut and reduces blood flow to your stomach to save oxygen and nutrients for more vital organs like the heart and the brain. These changes to your gastrointestinal system can be perceived as the discomfort linked to fear and anxiety. <h2>It all goes back to the brain</h2> All bodily sensations, including those visceral feelings from your chest and stomach, are relayed back to the brain through the pathways <a href="https://www.ncbi.nlm.nih.gov/books/NBK555915/">via the spinal cord</a>. Your already anxious and highly alert brain then processes these signals at both conscious and unconscious levels. <a href="https://doi.org/10.1176/appi.ajp.2016.16030353">The insula</a> is a part of the brain specifically involved in conscious awareness of your emotions, pain and bodily sensations. The <a href="https://doi.org/10.1038%2Fs41598-019-52776-4">prefrontal cortex</a> also engages in self-awareness, especially by labeling and naming these physical sensations, like feeling tightness or pain in your stomach, and attributing cognitive value to them, like “this is fine and will go away” or “this is terrible and I am dying.” These physical sensations can sometimes create a loop of increasing anxiety as they make the brain feel more scared of the situation because of the turmoil it senses in the body. Although the feelings of fear and anxiety start in your brain, you also feel them in your body because your brain alters your bodily functions. Emotions take place in both your body and your brain, but you become aware of their existence with your brain. As the rapper Eminem recounted in his song “Lose Yourself,” the reason his palms were sweaty, his knees weak and his arms heavy was because his brain was nervous.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/210871/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/arash-javanbakht-416594">Arash Javanbakht</a>, Associate Professor of Psychiatry, <a href="https://theconversation.com/institutions/wayne-state-university-989">Wayne State University</a> Image credits: Getty Images This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/if-anxiety-is-in-my-brain-why-is-my-heart-pounding-a-psychiatrist-explains-the-neuroscience-and-physiology-of-fear-210871">original article</a>.

Body

Over 60

News

Shop

Catalogues

Travel

Health

Lifestyle

Finance

Entertainment

Property

Information

Keep up to date

Search

What’s the difference between MSG and table salt? A chemist explains

Airlines cancel flights after volcanic eruptions. An aviation expert explains why that’s a good thing

Distraught bride explains why no one showed for her wedding

How do heat protectants for hair work? A chemistry expert explains

Readers response: What's a pain you can't truly explain until you've endured it?

What happens in an autopsy? A forensics expert explains

Yes, blue light from your phone can harm your skin. A dermatologist explains

Why do dogs have different coats? Experts explain – and give grooming tips for different types

Why do I poo in the morning? A gut expert explains

Why do we love to see unlikely animal friendships? A psychology expert explains

How do airplanes fly? An aerospace engineer explains the physics of flight

Hospice nurse explains why we shouldn't be afraid to die

How much stress is too much? A psychiatrist explains the links between toxic stress and poor health − and how to get help

Why do airlines charge so much for checked bags? This obscure rule helps explain why

Princess of Wales and King Charles: one in two people develop cancer during their lives – the diseases and treatments explained

Altitude sickness is typically mild but can sometimes turn very serious − a high-altitude medicine physician explains how to safely prepare

Mothers’ dieting habits and self-talk have profound impact on daughters − 2 psychologists explain how to cultivate healthy behaviors and body image

How to make a perfect romcom – an expert explains the recipe for romance

Does running water really trigger the urge to pee? Experts explain the brain-bladder connection

If anxiety is in my brain, why is my heart pounding? A psychiatrist explains the neuroscience and physiology of fear