Dehydration can impact your training in winter, just like in warmer temps!
It’s January, you’ve got some training to do, and it’s a gorgeous winter day. You opt to train outside to enjoy the brief sunshine before the early sunset. Later you discover that you’re dehydrated! How did this happen?! Read on to find out about hydration for winter sports.
Cold air has less water vapor than warm air.
When breathing in cold, dry air and exhaling warm, moist air, you end up with a net loss of water. Also, many people experience an increased breathing rate just from being outside in the cold, independent of the exercise. Add in the training and you end up losing water over the course of the training session.
Are you actually getting in the water? (Don’t do this without acclimating!)
Athletes who decide to “swim through” the winter are a hardy breed. First, they acclimate by swimming through the fall, gradually getting used to colder and colder water. Please don’t just jump into icy water if you haven’t been swimming since August! Heat loss in cold water is about 4x that of cold air!
They also experience cold-induced diuresis, or the sudden urge to urinate. Jump in that cold water and there’s a swift increase in high-pressure baroreceptors in our bodies, leading to a plasma volume increase that must then be balanced by increased urine production.
How well did you dress for the weather?
If you dressed appropriately, you’ll sweat some in all the usual places.
If you dressed too heavily, or you have on clothes that don’t breathe, you can have a higher than usual sweat rate from heat trapped under clothing.
Dressing for the weather can make a huge difference in comfort during cold weather exercise!
Are you shivering?
The energy cost of shivering can be up to 6x greater than baseline. Granted, most people don’t do this for long; it should stop once you get into your exercise. And it won’t cause sweating. But still, it takes calories!
Want to really shiver? Start moving faster. Speed increases heat loss by convection.
Are you acclimatized to cold weather?
Cold acclimatization is the opposite of heat acclimatization. It means that you gradually get used to spending time in cold conditions. Your resting metabolic rate (the baseline calories you need to live through the day) increases from shivering and non-shivering thermogenesis from increased thyroid hormone and catecholamines. You might also get an increase in brown adipose tissue.
If you spend most of your time inside but just pop outside for a training session a couple of days a week, you’re not acclimatized. It takes time and consistent, frequent exposure to be truly acclimatized.
How do you hydrate and recover after cold weather exercise?
Consider warm fluids for rehydration, and probably more than you think you’ll need! Soups, lattes (dairy or non-dairy!), hot chocolate, hot tea, hot lemon water or tisanes all are good choices. Skratch has a few winter-specific sports drinks as well, like their hot apple cider and matcha green tea with lemon hydration powders.
Because of the higher metabolic rates from cold acclimatization and the fact that shivering burns carbs, you might need to eat more and possibly eat more carbs. At the very least, be careful about cutting calories in cold weather. It might may impair heat production.
Next Steps
Need to build the best latte you can? Here’s how to optimize your coffee drink, whether it’s a peppermint mocha or not. And here’s a list of low/no sugar, not sweet sports drinks for those who need sodium or just want a bit of flavor.
Find out more about heat loss by convection. And more about how the menstrual cycle might impact hydration needs!
Need help figuring out how to hydrate for your winter training? Contact Dr. Schubert here. Or check out the services offered!
References
Ross ML, Martin DT. Chapter 24: Altitude, Cold and Heat. In: Burke L, Deakin V, eds. Clinical Sports Nutrition. 5thEd. McGraw-Hill Education (Australia); 2015:774-776.
Murray B, Osterburg K. Chapter 6: Fluid, Electrolytes and Exercise. In: Karpinski C, Rosenbloom C. Sports Nutrition: A Handbook for Professionals, 6th Ed. Academy of Nutrition and Dietetics (Chicago); 2017:117.