The Big Chill, and How to Avoid It
The ARS Sojourner
Hypothermia, or exposure, is defined as the lowering of the bodyís core temperature to produce harm or illness. Once a person becomes hypothermic, it can be difficult to reverse it, especially in the wilderness. Therefore, the best measure of protection from hypothermia is prevention. Just a few extra supplies in the backpack can make the difference between hypothermia and warmth.
I have only been hypothermic once. It was a mild, borderline case which I was able to recognize quickly enough to do something about. It happened to be the night of the first Freeze Your B--- Off contest sponsored by the Arizona ScQRPions.
I felt cold. I was in that sleep state where one is partially awake but not fully aware. The only thing I knew was that I was very cold. What could I do laying on two ground pads in a tent atop a bed of snow? I toss and I turn--still cold. Iím so cold that slowly my brain begins to wake up and I become aware of my body.
My body is shivering, not a slight shiver which happens when youíre chilled but a real shiver vibrating through the whole body. I realize that I am not controlling the shiver and my body is doing it involuntarily.
Uncontrollable shivering. That rings a bell. I ponder what that means as I am still in that half-awake, half-asleep mode. Uh Oh! HYPOTHERMIA.
This is not good. My body is telling me that it is becoming hypothermic and Iíd better do something about it. So, what did I do? I had some of those shake-em-up, get-em-hot instant heat packets to warm up my icy toes, I put my fleece jacket back on and I ate a Tigerís Milk bar to boost my metabolism into producing some heat.
There are four basic ways that produce heat in the body.
1) Application of heat--the sun, clothing, fire, (cuddling with your tent buddy!)
2) Eating food--eating something causes your body to digest food releasing energy as heat.
3) Muscular Activity--moving your body and also shivering.
4)Reduction of blood flow--physiologically, the body constricts superficial blood vessels to preserve heat . The hands and feet become cold first as the body conserves warmth for the important core organs.
Similarly, there are four ways that the body loses heat.
1) Evaporation--perspiration from the skin and moisture from the breath contributes to the loss of heat from the body.
2) Convection--loss of heat from air movement such as the wind.
3) Radiation--the body radiates heat from large superficial areas such as the head and neck. 80% of the bodyís heat is lost through the head and neck.
4) Conduction--sitting on the snow, becoming wet, being in contact with cold objects all contribute to cooling of the body.
The object is to keep heat gain in excess of heat loss. Prevention of hypothermia is the best way to treat it! If headed into cold weather, be sure to have these basic clothing items.
+ Gloves + Warm hat + Thermal underwear + Waterproof jacket and pants + Extra pair of socks + Fleece (or other insulating material) jacket or shirt
These clothing items are the type which can be layered. The thermal underwear should be made of a wicking-type material such as polypropylene, thermax, or capilene. Cotton is to be avoided as it holds in moisture and will make you cold. A fleece jacket or shirt should be worn on top of the underwear and the waterproof jacket on top of that.
If you become hot, it is easy to take off layers as needed. Extra socks are nice in case your feet get wet from water, snow, or sweat. And, the old saying, ìIf your feet are cold, put on a hat,î is so true! When winter snow camping, I always sleep with a liner hat made of polypropylene-type material or my wool cap if it is really cold.
Hypothermia is potentially life-threatening. Learn to recognize some basic signs and symptoms and what to do for them.
Violent shivering, great fatigue, apathy, slurred speech, lack of judgment, forgetfulness, loss of coordination, stumbling, and confusion.
The first thing to do when dealing with a hypothermic person is to remove any wet clothing and replace with dry clothing. Have him/her breathe warm, moist air by placing something over the nose and mouth to prevent further heat loss. Give warm, not hot, liquids to drink. Handle the person gently.
If camping, get the person into a sleeping bag. You can place water bottles filled with hot water into the sleeping bag to warm it up. If everything fails, body-to-body contact is the best alternative.
Some other good measures in preventing hypothermia is to stay well-hydrated. Drink plenty of fluids. In cold weather we donít always feel the need to drink but it is very important.
Keep your energy up by eating complex-carbohydrates such as fruit and nut mix, energy bars, and/or bread. Keep warm and dry by wearing the proper clothing and quit early before becoming tired. Prevention is truly the key and your body will thank you for it!
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Lorraine Aubert, AC6XK, is an expert outdoorswoman and avid QRP operator who lives in Hemet, CA