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Is thirst a good predictor of dehydration?

<div class="theconversation-article-body"> <a href="https://theconversation.com/profiles/lauren-ball-14718">Lauren Ball</a>, <a href="https://theconversation.com/institutions/the-university-of-queensland-805">The University of Queensland</a> and <a href="https://theconversation.com/profiles/kiara-too-2243669">Kiara Too</a>, <a href="https://theconversation.com/institutions/the-university-of-queensland-805">The University of Queensland</a> Water is essential for daily functioning and health, and we can only survive <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC2908954/">a few days</a> without it. Yet we constantly lose water through sweat, urination and even evaporation when we breathe. This is why we <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC5957508/">have evolved</a> a way to regulate and maintain water in our bodies. Like other animals, our survival relies on a strong biological drive that tells us to find and drink water to balance fluid loss. This is thirst – a sensation of dryness in the mouth signalling we need to have a drink. This <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC5957508/">basic physiological mechanism</a> is controlled mainly by part of the brain’s “control centre”, called the hypothalamus. The hypothalamus <a href="https://www.ncbi.nlm.nih.gov/books/NBK535380/#:%7E:text=The%20hypothalamus%20is%20the%20region,and%20the%20control%20of%20appetite.">receives signals</a> from various regions of the body and in return, releases hormones that act as a messenger to signal the thirst sensation. <h2>What is dehydration?</h2> Staying hydrated (having enough water in our bodies) is important for <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC2908954/">several reasons</a>, including: <ul> <li>regulating body temperature through sweat and respiration</li> <li>lubricating joints and eyes</li> <li>preventing infections</li> <li>digesting and absorbing nutrients</li> <li>flushing out waste (via the kidneys)</li> <li>preventing constipation</li> <li>brain function (including memory and concentration)</li> <li>mood and energy levels</li> <li>physical performance and recovery from exercise</li> <li>skin health.</li> </ul> Dehydration occurs when our body doesn’t have enough water. Even slight drops in fluid levels have <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC2908954/">noticeable consequences</a>, such as headaches, feeling dizzy, lethargy and struggling to concentrate. <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC4874113/">Chronic dehydration</a> can pose more serious health risks, including urinary tract infections, constipation and kidney stones. <h2>What does the evidence say?</h2> Despite thirst being one of the most basic biological drivers for good hydration, science suggests our feelings of thirst and subsequent fluid intake don’t always correlate with hydration levels. For example, a <a href="https://www.mdpi.com/2072-6643/16/18/3212">recent study</a> explored the impact of thirst on fluid intake and hydration status. Participants attended a lab in the morning and then later in the afternoon to provide markers of hydration status (such as urine, blood samples and body weight). The relationship between levels of thirst in the morning and afternoon hydration status was negligible. Further, thirst may be driven by environmental factors, such as access to water. For example, <a href="https://www.sciencedirect.com/science/article/pii/0031938484901549">one study</a> looked at whether ample access to water in a lab influenced how much people drank and how hydrated they were. The link between how thirsty they felt and how hydrated they were was weak, suggesting the availability of water influenced their fluid intake more than thirst. Exercise can also <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC6893511/">change our thirst mechanism</a>, though studies are limited at this stage. Interestingly, research shows women experience thirst more strongly than men, regardless of hydration status. To understand <a href="https://www.sciencedirect.com/science/article/pii/S2475299123148852">gender differences in thirst</a>, researchers infused men and women with fluids and then measured their thirst and how hydrated they were. They found women generally reported thirst at a lower level of fluid loss. Women have also been found to respond more <a href="https://www.mdpi.com/2072-6643/16/18/3212">to feeling thirsty</a> by drinking more water. <h2>Other ways to tell if you need to drink some water</h2> While acknowledging some people will need to drink more or less, for <a href="https://theconversation.com/dont-like-drinking-plain-water-10-healthy-ideas-for-staying-hydrated-this-summer-191859">many people</a>, eight cups (or two litres) a day is a good amount of water to aim for. But beyond thirst, there are many other ways to tell whether you might need to drink more water. 1. urine colour: pale yellow urine typically indicates good hydration, while darker, concentrated urine suggests dehydration 2. frequency of going to the toilet: <a href="https://www.ncbi.nlm.nih.gov/books/NBK291/">urinating regularly</a> (around four to six times a day) indicates good hydration. Infrequent urination can signal dehydration 3. skin turgor test: gently <a href="https://www.healthline.com/health/skin-turgor#test">pinching the skin</a> (for example, on the back of the hand) and observing how quickly the skin returns to its normal position can help assess hydration. Slow return may indicate dehydration 4. mouth and lips: a dry mouth or cracked lips can be early signs of dehydration 5. headaches and fatigue: frequent headaches, dizziness, or unexplained fatigue can be <a href="https://www.tandfonline.com/doi/full/10.1080/07853890.2019.1628352">signs of inadequate hydration</a> 6. sweating: in physically active people, monitoring how much they sweat during activity can help estimate fluid loss and hydration needs. Higher levels of sweat may predispose a person to dehydration if they are unable to replace the fluid lost through water intake These indicators, used together, provide a more comprehensive picture of hydration without solely depending on the sensation of thirst. Of course, if you do feel thirsty, it’s still a good idea to drink some water.<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/242194/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/lauren-ball-14718">Lauren Ball</a>, Professor of Community Health and Wellbeing, <a href="https://theconversation.com/institutions/the-university-of-queensland-805">The University of Queensland</a> and <a href="https://theconversation.com/profiles/kiara-too-2243669">Kiara Too</a>, PhD candidate, School of Human Movement and Nutrition Sciences, <a href="https://theconversation.com/institutions/the-university-of-queensland-805">The University of 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/is-thirst-a-good-predictor-of-dehydration-242194">original article</a>. </div>

Body

What happens to your body when you're dehydrated?

Water is essential for human life. It <a href="https://books.google.com.au/books?id=yNVYZopJWlkC&pg=PA215&lpg=PA215&dq=water+50-70%25+of+body+weight&source=bl&ots=CBnXnAeebN&sig=dKK09BVRvNJwwtYknQhoGqpeqIs&hl=en&sa=X&ved=0ahUKEwir_biXmM7KAhWD3KYKHXLuAbwQ6AEIIDAB#v=onepage&q=water%2050-70%25%20of%20body%20weight&f=false">accounts for</a> for 50-70% of our body weight and is crucial for <a href="http://www.ncbi.nlm.nih.gov/pubmed/16028570">most bodily functions</a>. Any deficit in normal body water – through dehydration, sickness, exercise or heat stress – can make us feel rotten. First we feel thirsty and fatigued, and may develop a mild headache. This eventually gives way to grumpiness, and mental and physical decline. We continually lose water via our breath, urine, faeces and skin. Most healthy people regulate their body’s water level remarkably well via eating and drinking, and are guided by appetite and thirst. But this is <a href="http://www.tandfonline.com/doi/abs/10.1080/07315724.2007.10719661?journalCode=uacn20#.VnHh1JN95Bw">more difficult</a> for infants, the sick, the elderly, athletes, and those with strenuous physical occupations, especially in the heat. <h2>What happens when you dehydrate?</h2> By the time you feel thirsty your body is already dehydrated; our thirst mechanism lags behind our actual level of hydration. Research shows that as little as 1% dehydration <a href="http://www.ncbi.nlm.nih.gov/pubmed/17921465">negatively affects</a> your mood, attention, memory and motor coordination. Data in humans is lacking and contradictory, but it appears that <a href="http://www.ncbi.nlm.nih.gov/pubmed/26381562">brain tissue fluid decreases</a> with dehydration, thus reducing brain volume and temporarily affecting cell function. As you “lose” body water <a href="http://onlinelibrary.wiley.com/doi/10.1002/cphy.c130017/pdf">without replacing it</a>, your blood becomes more concentrated and, at a point, this triggers your kidneys to retain water. The result: you urinate less. The thicker and more concentrated your blood becomes, the harder it is for your cardiovascular system to compensate by increasing heart rate to maintain blood pressure. When your dehydrated body is “pushed” – such as when exercising or faced with heat stress – the risk of exhaustion or collapse increases. This can <a href="http://www.aafp.org/afp/2011/0901/p527.pdf">cause you to faint</a>, for instance, when you stand up too quickly. Less water also hampers the body’s attempts at regulating temperature, which can cause <a href="https://en.wikipedia.org/wiki/Hyperthermia">hyperthermia</a> (a body temperature greatly above normal). At a cellular level, “shrinkage” occurs as water is effectively borrowed to maintain other stores, such as the blood. The brain senses this and triggers an increased sensation of thirst. <h2>How much should I drink?</h2> Normal water needs range drastically due to a <a href="http://www.ncbi.nlm.nih.gov/pubmed/16028570">number of factors</a>, such as body composition, metabolism, diet, climate and clothing. Surprisingly, the <a href="http://iom.nationalacademies.org/reports/2004/dietary-reference-intakes-water-potassium-sodium-chloride-and-sulfate.aspx">first official recommendation</a> about water intake was made as recently as 2004. According to the Institute of Medicine, the <a href="http://iom.nationalacademies.org/%7E/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Electrolytes_Water.pdf">adequate water intake</a> for adult men and women is 3.7 and 2.7 litres per day, respectively. Around 80% of total daily water should be obtained from any beverage (including water, caffeinated drinks and alcohol!) and the remaining 20% from food. But of course, this is just a rough guide. Here’s how to <a href="http://www.tandfonline.com/doi/abs/10.1080/07315724.2007.10719661?journalCode=uacn20#.VnHh1JN95Bw">monitor your own hydration</a>: <ol> <li> Track your body weight and stay within 1% of your normal baseline. You can work out your baseline by averaging your weight (just out of bed, before breakfast) on three consecutive mornings. </li> <li> Monitor your urine. You should be urinating regularly (more than three to four times per day) and it should be a pale straw or light yellow colour without strong odour. If less frequent, darker colour or too pungent, then drink more fluids. </li> <li> Be conscious about drinking enough fluids. Your fluid consumption should prevent the perception of thirst.<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; text-shadow: none !important;" src="https://counter.theconversation.com/content/50462/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> </li> </ol> Written by Toby Mündel, Senior Lecturer, School of Sport and Exercise, Massey University. Republished with permission of <a rel="noopener" href="https://theconversation.com/health-check-what-happens-to-your-body-when-youre-dehydrated-50462" target="_blank">The Conversation</a>.

Body

How to tell if you are dehydrated

Our bodies are made up of 70 per cent water, so when you’re dehydrated, you are compromising yourself from essential nutrients that are necessary to live a healthy life. While it may seem like dehydration is the simple act of drinking more water, in some cases, the issue can escalate and cause serious problems if pushed to the final stage. So, what is dehydration? When the term dehydration is used, people are generally referring to what medical professionals call “volume depletion” or hypovolaemia. Volume depletion is a reduction in the volume of water in the blood vessels. But dehydration is not the same as hypovolaemia and is something that occurs less frequently. Dehydration is the loss of water from both the body’s cells and blood vessels. Water is responsible for many of the things that require our bodies to function, such as our circulatory, respiratory, gastrointestinal and neurological systems. If taken too far, volume depletion can result in shock and collapse which, if not resuscitated in time, can be fatal. Signs of dehydration If you weigh 70kg, 40kg of that weight is water. So now that you have an indication of just how much water is stored in our bodies, let’s get into how you can decide whether you need an extra boost of hydration. The symptoms of volume depletion are as follows: <ul> <li>Thirst or a dry mouth</li> <li>Dizziness or low blood pressure</li> <li>If in the critical stages, confusion, due to lack of oxygen reaching the brain</li> <li>Your skin doesn’t bounce back right away when pinched</li> <li>Increased heart rate</li> <li>Weight loss</li> </ul> Those especially vulnerable to dehydration are elderly people as the amount of water our body stores reduces as we age. Combine that with other health problems such as chronic kidney disease, dehydration can pose a serious risk to those in a senior age bracket. In order to remain healthy and hydrated, keep an eye out on your water levels, and if you experience any of the above symptoms, start drinking plenty more water and see your GP if necessary.

Body

The difference between dry and dehydrated skin

With an extensive background in pharmacology and a thorough understanding of NIVEA core ingredients, <a href="http://www.nivea.com.au/" target="_blank">NIVEA</a> Skincare Expert, Robyn Hutch, has a passion for the intrinsic composition of the skin, and solving common skincare problems. It’s time to set the record straight to ensure you’re giving your skin the care it needs this winter. It’s the same story year in, year out – with winter well on its way, we all look to start planning ahead to care for our skin from top-to-toe in the cooler seasons. However, before you select your winter skincare arsenal, let’s take a closer look at our skin to determine whether it is dry or dehydrated. Most people believe these are the same skin conditions, as both tend to look the same, however this is certainly not the case! Not only is there a difference between dry and dehydrated skin, but also the characteristics of the two very different issues which each require a specific skincare regime. Dry Skin What is it? Dry skin is actually a skin type, rather than condition, which can be attributed to a lack of oil in the skin. Oils are produced naturally within the skin, which act as a barrier to help retain moisture. If the amount of oil within our skin is impaired, the skin struggles to retain this moisture which can in turn also affect the absorption of specific products. How can it be identified? Dry skin typically looks quite dull and flaky and can feel very tight. You might also notice that your skin is easily irritated, with the issue becoming more prevalent as you age due to a decrease in sebum production. What’s the solution? Dry skin needs a nourishing product to help replenish the lipids in the epidermis. This includes ensuring your skin receives daily care to help rejuvenate and maintain these essential lipids. Products that contain almond oil are particularly effective, as this popular skincare ingredient contains essential nutrients which support the barrier function of the skin. There are also a range of other skincare ingredients which can help combat dry skin, including: provitamin B5, aloe vera and argan oil. Dehydrated skin What is it? A problem that can come about any time of the year, dehydrated skin is a condition caused by a lack of water, or moisture in the skin. The condition can often result in oily skin or breakouts, and can be exacerbated by a range of factors including exposure to environmental elements – especially with the use of heaters and the cold winter weather. In extreme cases, dehydrated skin can lead to dry skin. How can it be identified? Dehydrated skin can feel both dry and oily at the same time, so it can often lead to confusion when looking for the most appropriate treatments. Dehydrated skin can also feel flaky and as a result, can often feel itchy. What’s the solution? Dehydrated skin requires water rich products in order to replenish the lack of moisture within the skin. A change in diet, environment and care regime can help also help address dehydrated skin, limiting the excessive use of heaters and extremely hot showers where possible. Do you suffer from dry skin? If so, what do you do to tackle it? Let us know in the comments below. Related links: <a href="/lifestyle/beauty-style/2016/05/chemicals-in-beauty-products-to-avoid/">Chemicals in beauty products everyone should avoid</a> <a href="/lifestyle/beauty-style/2016/05/diy-skin-care-tips-that-are-bad-for-you/">5 DIY skin care tips that are bad for you</a> <a href="/lifestyle/beauty-style/2016/04/home-remedies-for-sagging-skin/">5 home remedies for sagging skin</a>

Beauty & Style

Why you should use body oils for dehydrated skin

If the lotion just isn't cutting it in terms of moisturising, then body oil is going to become your friend. We have a few secrets to share about them. After a summer of dehydrating sunlight and conditioned air, it's no wonder your skin can resemble that of a lizard. All that swimming in salt water and chlorine only makes matters worse. Now is the time to try and undo the damage. However, sitting in front of a heater all day is far from helping. Instead of relying on your moisturising body wash to do all the work, there's something you can do beforehand to help your skin out. The idea may seem a little cuckoo, but have a go at applying body oil generously to your skin before you shower. Doing this works by protecting the skin from the harshness of the water – although it's easy to think that water doesn't damage the skin, in fact it does and hot water, which we are all most inclined to opt for, is even worse. Water strips the skin of the protective layer that lays on the epidermis (our outer layer of skin), which we all naturally have, which in turn opens the door for dryness. Constant showering, swimming, spas all wreak havoc with hydration. And why stop there? Amp up the moisture levels even more by repeating this step once you have got out of the shower to lock in hydration and keep it in. Layering is also an option – why not apply body oil and then follow this up by adding a body lotion to the mix. This will sink beautifully into the skin and give you a longer-lasting feeling of protection. Choices aside, the most important thing to remember is that applying something to your skin to retain moisture and rehydrate thirsty skin will work wonders for you this season. Written by Sarah Simpson. First appeared on <a href="http://www.stuff.co.nz/" target="_blank">Stuff.co.nz.</a> Related links: <a href="http://www.oversixty.co.nz/lifestyle/beauty-style/2016/02/how-to-make-your-own-facemask/">How to make your own face mask</a> <a href="http://www.oversixty.co.nz/lifestyle/beauty-style/2016/01/make-beauty-products-last-longer/">12 tricks to save every last drop of beauty product</a> <a href="http://www.oversixty.co.nz/lifestyle/beauty-style/2016/01/natural-ways-to-reduce-dark-skin-spots/">7 natural ways to reduce dark spots</a>

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Is thirst a good predictor of dehydration?

What happens to your body when you're dehydrated?

How to tell if you are dehydrated

The difference between dry and dehydrated skin

Why you should use body oils for dehydrated skin

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