Used with permission from www.jeffgalloway.com and by Nancy Clark, MS RD
Some athletes embrace winter’s chill as a welcome change from exercising in summer’s heat. But others complain about hating cold weather. If that’s your stance, remember that exercising with proper nutrition (and layers of dry clothing) offers the opportunity to chase away the chills. After all, an aerobic workout can increase your metabolism by 7 to10 times above the resting level. This means, if you were to exercise hard for an hour and dissipate no heat, you could raise your body temperature from 98.6 to 140 F. (You’d cook yourself in the process!) In the summer, your body sweats heavily to dissipate this heat. But in the winter, the warmth helps you survive in the cold environment. Runners can enjoy a tropical environment in their running clothes within minutes of starting exercise.
Because food provides the fuel needed to generate this heat, the right sports diet is particularly important for runners and other athletes who are exposed to extreme cold. Following are some common Q&A about winter and nutrition that offers tips to help you enjoy running during the winter season.
What’s the big nutritional mistake made by winter athletes? Failing to drink enough fluid is a major problem among winter athletes – runners, skiers, and winter hikers alike. Cold blunts the thirst mechanism; you’ll feel less thirsty despite significant sweat loss (if you overdress), to say nothing of respiratory fluid loss. That is, winter athletes need to consciously consume fluids to replace the water that gets lost via breathing. When you breathe in cold dry air, your body warms and humidifies that air. As you exhale, you lose significant amounts of water. Some winter athletes purposefully skimp on fluids because urinating can be problematic – too much hassle to shed layers of clothing. Yet dehydration hurts performance even in the wintertime.
Why do I feel hungrier in the winter than in the summer? A drop in body temperature stimulates the appetite and you experience hunger. Hence, if you become chilled during winter exercise (or when swimming, for that matter), you’ll likely find yourself searching for food. Eating “stokes the furnace,” generates heat, and helps warm your body. Food’s overall warming effect is known as thermogenesis (that is, “heat making”). Thirty to sixty minutes after you eat, your body generates about 10% more heat than when you have an empty stomach. This increased metabolism stems primarily from energy released during digestion. Hence, eating not only provides fuel but also increases heat production, warmth.
Do I burn more calories when I exercise in the cold? Cold weather itself does not increase calorie needs. You don’t burn extra calories unless your body temperature drops and you start to shiver. (And remember: the weather can actually be tropical inside your exercise outfit.) Your body does use a considerable amount of energy to warm and humidify the air you breathe when you exercise in the cold. For example, if you were to burn 660 calories while cross-country skiing for an hour in 0º F weather; you may use about 23 percent of those calories to warm the inspired air. In summer, you would have dissipated this heat via sweat. In winter, you sweat less. If you are wearing heaving clothes, you will burn a few more calories to carry the extra weight of skis, boots, heavy parka, snow shoes. The Army allows 10% more calories for the heavily clad troops who exercise in the cold. But the weight of extra clothing on, let’s say, winter runners is generally minimal….
Why do I find myself shivering when I get cold? Shivering is involuntary muscle tensing that generates heat and offers a warming effect. When you first become slightly chilled (such as when watching a football game), you’ll find yourself doing an isometric type of muscle tensing that can increase your metabolic rate two to four times. As you get further chilled, you’ll find yourself hopping from foot to foot and jumping around. This is Nature’s way to get you to generate heat and warm your body. If you become so cold that you start to shiver, these vigorous muscular contractions generate lots of heat—perhaps 400 calories per hour. Such intense shivering quickly depletes your muscle glycogen stores and drains your energy. This is when you’ll be glad you have some emergency food in your pocket!
What’s best to eat to warm myself up? If you become chilled by the winter weather, the best way to warm yourself up is to consume warm carbohydrates – hot cocoa, mulled cider, and steaming soup, as well as oatmeal, chili, and pasta. The warm food, added to the thermogenic effect of eating, contributes to rapid recovery. So bring out the thermos of soup!
So bottom-line, you’ll stay warm if you dress right, fuel well, and drink fluids to prevent dehydration.