As temperatures across the UK continue to climb to record highs, it is important that staying hydrated does not slip down the priority list. Dehydration is very common during heatwaves and can range from mild to severe, explains Dr Naveed Asif, GP at The London General Practice.
“Most of us are probably mildly dehydrated the majority of the time and experience things like a dry mouth, dry lips and dry eyes,” says Asif. “Then once it goes into moderate that means it is beginning to impact you more, and then we have the more severe side where you can become significantly unwell with it. In addition, if you have pre-existing medical conditions, even if they are mild, suddenly dehydration can just exacerbate them and make those symptoms significantly more uncontrolled.”
While thirst and a dry mouth are widely recognised signs of dehydration, there are several more subtle and surprising symptoms that can also signal that your body needs more fluids. Here are six more unexpected signs to look out for.
1. Mood Changes
“When people get quite dehydrated they might get a bit restless or irritable,” says Dr Hugh Coyne, co-founder of Coyne Medical. “This is because the brain is really sensitive to our level of hydration. People might notice that they feel a little bit more tense and agitated when they wake up on a hot morning and really want to have a drink of water straight away.”
2. Muscle Cramps
“The body is full of water and electrolytes, and electrolytes are the salts that make the body function and muscles work. If they are not diluted by water and are too concentrated, because you have not drunk enough water, that can cause flare-ups of cramping and tingling in your body,” explains Asif. “It means that the nerves that control the muscles are not working as efficiently, and often the muscles begin to seize up, because they just cannot function.”
3. Headaches
“It is quite common, even with relatively subtle dehydration, to get a headache,” says Coyne. “When our total body water goes down, the brain becomes a little bit dehydrated and you can get a transient shrinkage of the brain tissue where it becomes not as plump as it normally is. That can cause a little bit of tension and traction on the meninges, which is the lining of the brain, along with a little bit of decreased blood flow to the brain and a little bit of increased pain sensitivity.”
4. Changes in Skin Elasticity
“One thing that we also look at is something called skin turgor, which is the elasticity of the skin,” says Coyne. “When we suspect people are dehydrated, we take a gentle pinch of the skin, usually on the back of a patient’s hand, and then let it relax. In healthy, well-hydrated skin, we see that the elasticity of the skin is retained and bounces back quickly, but when people are a little bit dehydrated, that takes a little while to settle down.” However, this can be more difficult to see in older adults. “Signs of dehydration are often not quite as obvious in older adults, particularly with skin turgor, because they tend to lose that skin elasticity that younger people have naturally over time,” explains Coyne.
5. Fatigue
“Fatigue, tiredness and lethargy are also common early signs of dehydration,” says Coyne. “That feeling that you need to plonk down on a sofa indicates that you might be inadequately hydrated.”
6. Increased Heart Rate
“People might notice that their heart rate is a bit elevated when they are dehydrated,” says Coyne. “The heart rate increases when we are dehydrated and have a relatively low amount of total body fluid to maintain the blood pressure and maintain the perfusion of blood supply to the key organs.” Asif adds: “The body also releases additional stress hormones, such as adrenaline, endorphins, and cortisol, to try and speed up the heart and speed up the process to increase delivery of vital blood and the associated salts and fluids to our vital muscles and organs.”
Why Is It Important to Not Ignore Signs of Dehydration?
“If dehydration worsens it can lead to very severe illness, such as heat stroke or exertional heat stroke which is very severe and has high mortality rates,” says Coyne. “Therefore, it is very important that dehydration is addressed, and is prevented in the first place.” Significant mental changes should be checked out by a doctor. “Any signs of altered mental status, such as confusion or agitation, slurred speech and loss of consciousness requires emergency help because they are characteristic features of heat stroke,” says Coyne. However, he advises that higher risk groups should be extra cautious and seek help at a lower threshold. “Certain population groups, such as infants and older people, have a lower threshold to be seeking medical attention because when these two groups are affected the symptoms can be a little bit more subtle or difficult to discern,” says Coyne.
Tips on How to Stay Hydrated During a Heatwave
Don’t Wait Until You Are Thirsty
“Sometimes thirst can be a relatively unreliable indicator to drink more water, particularly in older adults, so I think it is important just to sip water throughout the day,” says Coyne. Asif agrees and suggests: “Rather than just having a sip, have 10 sips of water at once and do it regularly, so it does not feel like you are reminding yourself to stay hydrated.”
Look After Your Skin
“Make sure that you are applying moisturiser to make sure that your skin stays hydrated,” advises Asif.
Consider Electrolytes When Exercising
“If you are going for a run or a cycle for less than an hour, water should be fine, but generally it is recommended to have a carbohydrate-electrolyte sports drink on a longer ride or run,” says Coyne.
Stay Cool
“Try to create a cool environment by keeping the blinds down and the air conditioning on,” recommends Coyne. “Fans and misting can also really help.”
Monitor Your Urine Colour
“You want it as clear as possible, and if it is beginning to get darker and darker, that is your body telling you that you need to drink more, so you are aiming for light yellow or almost clear colour,” says Asif.
