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As the weather turns colder, many intrepid triathletes continue to brave the elements to get in their workouts. You may be heading out for a trail run, hike, snowshoe, cross country ski or fat bike for fun, but you still need to pay attention to how well you hydrate.
What happens when you workout out in the cold
Nick Suffredin, a race day fueling expert, avid triathlete and Director of Research and Development for Post Holdings Active Nutrition Division, explains how your body reacts differently when you train in the cold versus warmer conditions. “With every breath in the cold air you lose a great deal of fluid,” he says. “When you add on the amount of extra clothing you are exercising in and you are still perspiring, typically your body will have to work much harder than it normally would due to the extra weight. Don’t forget that sweat evaporates quicker in the cold, dry air.”
To make things worse, Suffredin points out that your thirst response is not as active in cold temperatures as it is in warm temperatures. So while your body may be working harder, you won’t feel as thirsty. This leads to not drinking enough during their workouts and becoming dehydrated. For longer sessions, say a cross country ski workout, this can be a very big problem.
Andy Blow, the founder of Myh2pro, agrees saying, “If you’re working hard, you won’t sweat much less than you do in the summer. Bear that in mind for all of your high intensity winter sessions your hydration needs will still be pretty large.”
Learn your sweat rate
The first step to ensuring that you have a good winter hydration plan is to know what your sweat rate is. Sweat rate is very individual and depends on your current fitness, gender, clothing, level of acclimation to the conditions and more. Even if you have done a sweat rate test before, it’s worth doing one in cold temperatures to see how different conditions may affect your sweat rate.
To learn your sweat rate, start by recording your nude body weight prior to exercising. When you are done, dry yourself off the best you can and record your nude body weight again. Record what and how much you consumed of fluids during your exercise. Subtract your pre-exercise weight from your post-exercise weight and add the amount of fluid you consumed to that number. This tells you the amount of fluid you lost while exercising. Then divide that number by the amount of hours you exercised for and that will equal your sweat rate. Record the weather conditions to see how your sweat rate fluctuates.
Staying warm is not just about being comfortable. Blow points out that if you don’t stay warm, you can lose extra fluid through cold diuresis. Cold diuresis typically occurs during mild to moderate hypothermia. It is believed to be caused by blood being redirected from your extremities to your core. This causes the arterial cells of your kidneys to sense a rise in blood pressure and as a result your kidneys excrete more fluid to balance out the pressure. In turn, the kidneys produce more urine, filling your bladder and creating the urge to urinate. The more often you go to the bathroom, the more fluid you will lose. While the basic concept is not overly complex, this phenomenon is still not completely understood by scientists and it does seems to affect some people a lot more than others.
Preventing cold diuresis is fairly straightforward. Dressing warm enough, paying special attention to your hands and feet, will keep your body from sending too much blood to your core.
Hydration guidelines and advice
“In general, overall fluid and electrolyte requirements will be a bit lower than they are in the summer for most athletes,” says Blow. “However with the above points plus the fact that most of the sweating that happens to athletes in training is driven by their work rate not just the environment it is true that you’ll need to keep an eye on hydration in the winter and not just worry about it when the summer comes around again.”
Your hydration goal of any workout should be to minimize fluid loss. The standard guidelines of approximately 16 to 20 ounces of fluid per hour still apply during the winter. With a repressed thirst mechanism, you may want to se a timer on your watch for every 15 to 20 minutes to remind yourself to take a drink. Plus, there are several great drinks on the market that are designed to be warmed up for colder weather. Pour them into an insulated bottle for a drink that will not only hydrate you but also keep you warm.
Winter training can be as difficult as what you do in the summer, so be prepared. Dress warmly, make sure you bring enough hydration with you, and drink at regular intervals. These simple steps will keep you training through the cold and enjoying your workouts.