This article was originally posted in the Winter-Spring 2009 issue Your National Forests magazine.
Myth: You lose most of your body heat through your head.
If you haven’t heard this one, you probably haven’t dressed for the cold... ever. The amount of total body heat you can lose through your head, according to the myth, varies from half to as much as 85 percent. But your head accounts for only 10 percent of your total body surface! And, guess what, that’s exactly how much body heat you lose from your head—10 percent. You do not lose heat faster or more easily from your uncovered head. But 10 percent is more than enough to be concerned about, and ears and noses remain high on the list of favored sites for frostbite. Bundle up your noggin.
Myth: Drinking hot liquids warms you faster than drinking cold liquids.
There should be little misunderstanding about hydration: you must be drinking to maximize internal heat production and to perform at your best. You need at least as much fluid in winter as in summer. It is, however, almost impossible to drink enough hot liquid to raise the temperature of your body’s core. And you can drink cool water much faster than you can sip down a hot drink. Yes, there is a psychological lift gained from a warm mug, but don’t count on it to warm you up inside. Most of the time, drink cool or cold liquid, preferably water, to stay warm in winter.
Myth: A little nip of alcohol helps prevent cold injury.
Sipping your favored alcoholic beverage on a winter trail might make you feel good, but it is dangerous outside in cold weather. Alcohol opens up blood vessels in your skin (the warm blush of drinking), but that encourages loss of heat from your skin. And alcohol lowers your core temp a bit. “Ah,” you say, “what if I’m dressed appropriately?” You might not lose a dangerous amount of heat if your skin is adequately protected, but you will lose the keen edge of mental sharpness. Save the toddy for chats by the fireplace at home, or at least until camp is well set and you only have to crawl to your sleeping bag. Even then, moderation in all things
Myth: Hypothermia kills you within minutes of falling into icy water.
Those who die within minutes of plunging into deeply cold water drown: they panic, inhale, go down, and never come up. Hypothermia, the dangerous lowering of your body’s core temperature, takes at least a half hour to become a problem, even in ice water. Gordon Giesbrecht, Ph.D., the guru of cold-weather medical research, suggests using the first minute after an unintentional coldwater dunking to calm down and control your breathing. Then, he says, use the next 10 minutes trying to get out of the water. After 10 minutes, the cold will have sapped your ability to move usefully. If you can’t get out, try to relax and float. You have about an hour more of consciousness. Those wearing a personal flotation device might survive long enough to be rescued.
Myth: In a hard, cold wind, your skin freezes faster.
Actually, this is partially true. High-speed wind dramatically lowers the temperature of your unprotected skin. And the faster the wind, the more quickly your skin cools. However, there is no incremental difference in the effect of wind on your skin at wind speeds over 40 miles per hour. But winds that high drive most people into shelter anyway. The myth is this: a cold wind can cause frostbite in temps above freezing. Wind increases the rate of heat lost, but it will not lower your skin temp below the ambient temperature. If the thermometer reads above freezing, a high wind can cause you great discomfort, but it will not freeze your skin.