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Close-up of a person holding a mug to help prevent dehydration in the cold weather.

December 8, 2022 • read

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Why do I get dehydrated in the winter?

Dehydration seems like a hot weather problem. But sweating, thirst, and dehydration aren’t confined to torrid spring and summer weather. Maintaining your body’s moisture content can be a challenge during the winter months too.

In fact, cold weather can even fool you into thinking you’re fine when you’re actually in need of some water. Here’s how to avoid dehydration in winter.

What causes dehydration during the winter months?

Cold weather alone causes dehydration to a certain degree. Cold air is much dryer — it just can’t hang on to moisture like warm air. So the colder the temperature, the more quickly water in the environment evaporates.

This makes the simple act of breathing a contributing factor to fluid loss during the colder months. Because the air is so chilly, your body has to both warm and moisten it before it hits your lungs. Once you exhale, that warm humid air is gone — taking its moisture with it.

Breathing isn’t the only mechanism for dehydration during the winter, though. Your body undergoes certain processes when it’s cold out in its attempt to keep you warm. One of the side effects of these can be fluid loss.

When you’re cold, your body aims to conserve heat by constricting your blood vessels. This prevents blood from flowing freely throughout your body, keeping more warm blood close to your core. If you find you often get cold hands in the winter, this is why.

While all this blood in your core does the trick of keeping your organs toasty and protected, it also keeps your body from noticing fluid loss as easily. As a result, you don’t get as thirsty in the winter — even when you’re slightly dehydrated.

To make matters worse, all that blood rushing to your torso may actually cue your body to urinate more frequently. This phenomenon, known as cold weather diuresis, happens because the blood in your core causes your blood pressure to increase.

This triggers your kidneys to filter excess fluid from your blood in an attempt to bring your blood pressure down again. And voilà, the result is an increase in your need for bathroom breaks.

How exercising in cold weather can increase your risk of dehydration

Breathing and urination aren’t the only ways you lose fluids during the dry winter months. Cold weather exercise and its resulting perspiration can be another source. But, because sweat evaporates more rapidly in the cold air, sweating and fluid loss are less apparent.

Additionally, your sweat is more likely to get wicked away in winter by any bulky layers you wear. Both factors may contribute to dehydration, as staying hydrated during a winter exercise session might not seem as necessary as it does after a summer sweat.

This isn’t limited to just high-intensity exercise either. Walking during the winter or shovelling snow, for example, are both high activity enough to cause sweating and fluid loss. But because your body doesn’t heat up as much you might not notice how hard you’re working or that you’re actually sweating.

What are the signs and symptoms of dehydration in cold weather?

Because you may not experience the same extreme thirst cues during the colder months, dehydration might not be as apparent. Instead, be on the lookout for these other symptoms signalling winter dehydration:

  • Dark-coloured urine
  • Urinating less frequently than usual
  • Constipation
  • Dry lips or mouth
  • Dry skin
  • Fatigue
  • Headaches
  • Difficulty concentrating
  • Increased irritability
  • Reduced skin turgor or elasticity — if you pinch the skin and it doesn’t return to its normal shape right away, it’s a good indication that you’re dehydrated

In babies, dehydration can look like:

  • Crying without tears
  • Dry or sticky mouth
  • Fewer wet diapers
  • Crankiness

In more severe infantile dehydration cases you may see:

  • A sunken fontanelle (that soft spot on their head)
  • Sunken eyes
  • Drowsiness

What are the risks of becoming severely dehydrated during the winter?

You can usually deal with slight dehydration by drinking plenty of fluids. Ignoring early signs, however, can increase your risk for more severe dehydration, which is a medical emergency.

Your body is largely made up of water and without adequate fluids it can’t function properly. Severe dehydration can result in organ damage, affecting your kidneys, heart, and brain. Even if you recover from dehydration, it can have lasting effects on your organs.

Dehydration is especially hard on your kidneys. As it progresses, dehydration can cause waste to build up in your kidneys. This can damage these crucial organs, affecting their functioning and potentially contributing to kidney failure.

Your brain is also susceptible to fluid loss, and even a small fluid deficit can affect your cognitive abilities. Milder dehydration can induce headaches, concentration difficulties, and fatigue.

Once these symptoms give way to confusion and difficulty expressing yourself, it’s a good indication that you’re dealing with severe dehydration and need immediate medical care. Severe dehydration can have catastrophic effects on your brain functioning and may put you at risk of coma and even death.

Even when it’s not as intense, dehydration isn’t good for your body. Your body needs fluids to flush out its urinary tract periodically. Without a regular stream of urine to clear it out, bacteria near your genitals have more opportunity to make their way into your urethra. This means that dehydration can lead to urinary tract infections (UTIs).

Additionally, improper hydration can cause a build-up of calcium and uric acid in the kidneys. Over time, this may lead to arguably one of life’s most painful conditions — kidney stones.

Who is at greatest risk of dehydration in the winter?

Dehydration can happen to anyone, no matter the season. It happens more quickly, however, and is more likely to affect young children, pregnant women, and the elderly.

Older people may be especially at risk as thirst sensations diminish in the elderly. Babies and young children, however, may not be able to communicate their thirst as needed. Additionally, small amounts of fluid loss have a greater effect because of their size, increasing their odds of dehydration.

How do you prevent winter dehydration?

Preventing winter dehydration isn’t just a matter of avoiding the worst. Staying properly hydrated will also stop your energy levels from flagging and keep your digestion running smoothly. Here’s how to prevent dehydration all winter long:

1. Don’t wait for signs of dehydration before making your move. Stay hydrated even when you don’t feel thirsty by incorporating a good amount of water-rich foods into your diet. Think soups, but also fruits and vegetables like cucumbers, tomatoes, apples, and melon.

2. If you often forget to drink liquids, it’s probably time to invest in reusable water bottles. These can be kept in your car, at your desk, or wherever else you spend a lot of time. They’re a great way to cart water around while serving as a visual reminder that it’s time to drink up.

3. Set water goals throughout your day. If you have a bit of a commute in the morning, for example, aim to drink 500mL — the size of a typical bottle of water — before you get to work. Do this at predetermined times throughout the day to maintain adequate hydration.

4. Layer up. Bundling up is crucial for avoiding the worst of winter’s wrath and and to keep your body temperature warm. But all that hot, bulky clothing can make you sweat and contributes to moisture loss.To minimize this, layer up on those cold days, especially if you’re exercising. Peeling off layers as needed will keep you feeling toasty without causing overheating.

5. Liven up your water. Not everyone enjoys water. If you fall into this group, try adding some flavouring or fruit to it to make it more exciting. This can be especially helpful for toddlers or young children who might need a little more persuading to drink their fluids.

What should you do if you’re experiencing signs of dehydration?

Treating cold weather dehydration can’t be put off until later. If you’re experiencing mild dehydration, you can treat it at home, but it should be addressed immediately.

The obvious solution is to consume fluids, but not just any will do. Steer clear of beer or any alcoholic drinks, as these contribute to dehydration. Instead, stick to water, electrolyte-containing beverages that also up your sodium and potassium intake, or rehydration fluids. Avoid sugary sodas and juices if possible, as they’re high in sugar and low in electrolytes.

Moderate to severe dehydration, however, requires medical intervention. In this case, you’ll likely need to have your liquids replenished with intravenous fluids. This must be done at a hospital where they can also monitor your heart rate and blood pressure for safety.

How Maple can help if you’re dehydrated

Getting out and being active is a great way of enjoying the winter weather. But if you’re concerned that you’re showing signs of dehydration, it’s a good idea to speak to a doctor.

With Maple, you can connect with a Canadian-licensed doctor online within minutes. They can advise you on managing your dehydration symptoms at home. And if they’re concerned about your condition, they’ll be able to let you know if it’s time for emergency medical intervention.

Don’t let the cold stop you from staying active all winter long. Cold weather can cause dehydration, but with proper precautions, you can stay safe and have fun.

This blog was developed by our team and reviewed by a medical professional.

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