Dehydration in winter: How and why you keep losing water

It's extra important to monitor hydration status when temperatures drop.

Amanda Capritto
4 min read
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Dehydration is to summer as hypothermia is to winter -- but wait, maybe not. Dehydration is certainly a threat in the hot summer months, but it's just as much of a danger when temperatures drop. You can get dehydrated in the winter as easily as you can in the summer, if not more so, and the threat multiplies if you regularly exercise outdoors in the cold.

This is the case largely because, in cold weather, you may not notice how much water you lose. And if you don't feel thirsty, which is often the case in the winter, you may not replenish said lost water. Over the course of a few days or weeks, this can lead to serious dehydration. 

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Signs of dehydration

Dehydration occurs when you lose more fluids than you consume, and your body is left struggling to perform its usual -- and critical -- functions. Dehydration often presents first as minor headaches and fatigue, symptoms you might equate to something else initially, like a lack of sleep. 

As dehydration progresses, you might notice that you feel dizzy if you stand up too quickly; experience random muscle spasms and cramps; get a bad headache or migraine; and lose your ability to focus and concentrate.  

Severe dehydration can lead to dry skin and lips, sunken eyes, fainting spells, rapid heartbeat and rapid breathing. 

Through all of these stages, a common indicator that you're dehydrated is infrequent urination or urine that is dark in color. Kelly Barnes, a senior scientist at the Gatorade Sports Science Institute, tells CNET that monitoring your urine is the easiest way to keep an eye on your hydration status during rest (not while exercising). 

"If you are not going to the bathroom often, not producing enough when you go or if your urine is dark in color, then you probably need to consume more fluids on a more regular basis," Barnes says. But on the flip side, "If your urine is near constant and clear, then you may need to scale back drinking or drink smaller amounts more regularly."  


Rehydrate with an electrolyte-fortified drink to maximize replenishment of the nutrients lost through sweat.

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Why is it easier to get dehydrated in the winter? 

Dehydration is more of a threat in the winter because most people don't notice the fluids leaving their bodies. That, combined with decreased thirst, can bring on dehydration more quickly than you'd think. 

Diminished thirst response

When it's cold outside, people tend to feel less thirsty, Barnes says. There are physiological shifts that make this happen, but often, diminished thirst occurs simply because it's cold, so of course you don't crave cold (or even room-temperature) water. 

Increased respiratory water loss

Every time you "see your breath" when it's cold outside, that's water leaving your body and evaporating. The drier the air, the more water you lose this way, Barnes says. Respiratory water loss also increases as the intensity of your exercise increases: The heavier you breathe, the more vapor you produce with each breath. The faster you breathe, the more vapor you produce per minute.

Less obvious perspiration 

In sweltering summer weather, sweat is obvious -- the air is hotter and more humid, so sweat doesn't evaporate off of our skin quickly. In cold, dry weather, Barnes says that your sweat evaporates more rapidly, leaving less to accumulate or drip, if any. Since we usually equate "rehydrate" with "sweat," this may cause you to think that you don't need to replace as much fluid as you normally do, especially during exercise, Barnes says.


The drier the air, the faster your sweat evaporates, making it less noticeable. 

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How to beat dehydration in the winter

"The best precaution against dehydration in the cold is to be prepared," Barnes says. "Make sure that you are properly hydrated throughout the day and prepare to replace fluid loss during your workout." 

Your workout outfit is important, too, Barnes says: "Make sure that you wear the proper gear for your workout and for the weather to help you retain your body heat while allowing sweat to evaporate."

If you're struggling with dehydration because you just don't feel thirsty, Barnes recommends hydrating based on body mass change during exercise. Weigh yourself before you exercise and then replace enough fluid to keep yourself within 2% of your pre-exercise body weight.  

You should, however, still make a point to stay hydrated throughout the day and prior to your workouts. Choosing flavored beverages, such as sports drinks with electrolytes, is a good way to consume more fluid when you don't want plain water. If you want to sip on something warm, try caffeine-free herbal teas or decaf coffee. Caffeinated beverages are fine, too, but can act as a diuretic in some people, so it's usually best to drink them in moderation.

If you find that you are still unable to get enough fluids, try eating more foods with high water content. All fruits and most vegetables have high concentrations of water, and this can count toward your total daily water intake. 

If all else fails, make it fun: Get a water bottle you love and enlist a buddy or colleague to have daily water-drinking contests. Friendly banter can make even the most boring of things -- even drinking water -- more enjoyable.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.