Why you need to worry about dehydration when exercising in bitter cold

It's February 19th, yet here we are again with below-zero wind chills in the Chicago area. Competing or training in cold weather presents its own set of challenges. Dehydration – believe it or not – is a major issue. Here is why...

1. The body tries to keep your core warm
Normally your body carries blood to your extremities during exercise. But in the cold, your body preferentially tends to keep blood close to its core in order to stay warm. This increases your blood pressure, which will affect your kidneys and increase your need to urinate. 

2. Cold, dry air = more fluid lost
When you exercise in the cold, your lungs have to warm and humidify the incoming cold, dry air. Just by doing this, you can lose up to one quart of fluid daily. 



3. Concentration and focus is lost
Dehydration causes you to fatigue more quickly, affects your ability to maintain your core temperature, and decreases your concentration and focus. Unfortunately, success in many winter sports depends more on perfection of technique vs. cardiovascular capability (think skiing, snowboarding or even running on icy roads or trails). A decrease in focus is not something you want.

So how can you deal with this? 

First, it’s important to choose the right apparel. Wear clothes that are breathable and won’t cause your body to sweat excessively, resulting in more fluid loss.

Second, if you are planning a short-term cold weather experience, like skiing on a small hill or doing a shorter run, plan to take frequent breaks. Set an alarm on your phone or clock to remind yourself to visit the lodge for fluid and fuel or stop for water. However, if you are planning to be out for multiple hours – perhaps on a real ski or snowboard mountain or doing a long run, use hydration products. A camelbak, for examples, can be worn close to your body, which will prevent the fluid in it from freezing. Drink a few gulps every 15-20 minutes. 

Third, although you may be completely surrounded by it, eating snow is not a good idea. The energy you expend trying to warm the snow once inside your body will decrease your body temperature, potentially inducing hypothermia. 

Fourth, focus on your meals. Plan to eat a meal or snack before you exercise because increasing your metabolism will increase your core temperature. At all meals or snacks, choose foods such as soups and hot drinks that increase fluid intake and body temperature.

Be extraordinary,

RDKate