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Hypothermia

How to recognize and deal with it

Published online: Dec 05, 2002 Feature ?JOANN?ROE
How often have you said, while shivering on a cold slope, "Oh, well, I have thin skin from living in a warm place. I'll get used to it."
True, your body does make changes to accommodate temperature and altitude, but not instantly. You need to be aware of how the body protects itself from the assault of cold when traveling out of your accustomed climate.
This most insidious approach to hypothermia is not necessarily in extremely low temperatures, rather in cool, wet and windy conditions: wind chill. Let's say you are snowmobiling far from the warming hut.
According to Bill Boyd, the assistant fire chief in Bellingham, WA, and a paramedic, the body's first response to cold is, of course, shivering and shaking. It's a form of exercise to keep you warm. If not corrected, the situation progresses. Your hands and feet are cold. You realize that your reaction times have slowed; you can't think clearly. Your companion notices that your lips are turning blue and your face has a dull coloration. You actually stop shivering, because you have depleted so much energy (heat) in all that shaking. What is happening?
Without getting too technical, here is what happens to your body in such a situation. The body's monitors are keyed to keeping your vital organs (your body core) supplied with blood for life preservation. Under siege of cold, your blood volume is shunted to this core and retreats from your extremities. The concentration of blood volume creates an increase in urine production and fosters dehydration. Bereft of adequate circulation of blood (blood needs water) carrying heat and oxygen, the extremities receive insufficient heat and may become frostbitten. Maybe your limbs just feel numb.
It's critical now that you strip off wet clothing and don dry clothes. Get out of the wind, maybe by building a lean-to from brush or snow blocks. Eat high-energy food and drink liquids. Have a space blanket in your backpack-insignificant weight but a lifesaver-to keep body warmth in. Get into a sleeping bag, if you have one, and if dangling at the edge of hypothermia, ask a companion to get in there with you.
How do you prepare yourself for cold and hope to avoid such a situation? Harte Bressler of Bellingham, WA, a veteran of Mountain Search & Rescue for the North Cascades Mountains, gives some tips.
Clothing: It's important to be warm without perspiring. Layering is the way. Next to your skin should be thermal underwear, especially the type that wicks moisture out to the next layer, like Capilene synthetics. Next comes an insulation layer, preferably synthetic like a polyester fleece that will accept the moisture from the innermost layer. Then a warmth layer like a sweater and finally a rain or wind protector. The outerwear should breathe and some have pit zips under the arms so you don't perspire so much. You can peel off layers as necessary to avoid perspiration, since being wet is chilling.
Layering for the feet follows the same theory. Next to your feet should be a thin polypropylene, then heavy woolen socks in good boots. Wear waterproof gloves with light liners.
Wear a hat. Blood is close to the surface in the head and neck. They constitute only about 10 percent of the body but can account for as much as 50 percent of heat loss in freezing temperatures.
Don't forget the gear. Keep your backpack dry. You could be stuck out in the wild by unforeseen circumstances and a wet sleeping bag or jacket is worthless. You should carry a change of clothes for emergencies. An ordinary garbage bag over your backpack is an easy protection.
Liquids: We tend to think of liquid intake for heat not cold. Hydration is at least as important in the cold to maintain the blood volume circulation to your exercising muscles. Lack of water or dehydration contributes to fatigue and loss of heat. (And remember in cold our body creates more, not less urine.)


Food: Think of your body as a stove. It's more important to keep it stoked regularly than to have a big blaze at first. Nibble frequently on high energy or calorie-producing foods. Nibbling keeps a constant flow of heat or energy to your body, where a large meal takes blood away from the rest of the body for digestion. High-energy bars convert quickly to sugar like kindling. Complex carbohydrates such as granola and fruit are slower to burn but last longer and burn steadier. Fatty foods like peanut butter or bacon are the "logs" that are slow to start burning but last a long time. However, according to Bressler, fats do not convert as well as proteins and carbohydrates at higher elevation. Also because of its slow burn, fat is not the best for quick energy such as when you realize you are growing really cold.
Actual frostbite or hypothermia is a condition that requires careful medical monitoring, and you should get help at once. Consult a hypothermia expert before you go into the backcountry, at least, so that you know what you can do safely. A person with severe hypothermia needs very gentle and specific handling to avoid medical complications that include heart failure.
After 20 years with Mountain Search & Rescue, Bressler urges snow sports enthusiasts to stay put, if they are lost but have shelter, which could even be a dense evergreen tree, and water. Rescuers start where the person was last seen and, if you move away, it just makes it harder to find you.
Knowledge is power, and proper preparation will help you enjoy the freedom of the mountains and forests without concern. e
(Editor's Note: The author and Bressler are giving their best advice only and do not guarantee the satisfactory outcome of any situation described above. Roe is a writer on diverse topics for magazines and the author of 14 books as well. She is a resident of Bellingham, WA, a cross-country skier, occasional snowmobiler and ex-downhiller.)