Hypothermia, How to Dress to Avoid It

avoid hypothermia

Many years ago, I spent a winter at a military base near Chicago.  The wind from the Great Lakes made the place miserable, often the wind chill was below zero.  Every morning we had to get up and march to chow in the dark.  We did not have good cold weather gear and put on everything we had.  We did not have long underwear.  Our dress consisted of fatigues, field jacket with liner, and a cotton hat.  We would then put on our heavy dress overcoat and use a towel for a scarf.  We just had thin leather gloves and no decent headgear.  By the time we had marched a mile to the chow hall we were frozen and sometimes on the verge of hypothermia

Since then I have learned a lot about how to dress for cold weather.  Now since many of you know that I live in California, you may wonder how I learned.  Well I live in the foothills of the Sierra Nevada Mountains and have spent time near Lake Tahoe and Truckee which have lots of snow and gets very cold.

In cold weather, wear multi layers.  You should start with a good base of long underwear.  Avoid the cheap cotton long underwear sold in the discount houses.  Fleece, polypropylene, or wool retains most of their insulating properties when wet.  They are the best choices.  Cotton loses its ability to insulate when wet and may cause you to suffer from hypothermia.

You should then have a good intermediate layer.  The purpose of this layer is to keep heat in and cold out, which is accomplished by trapping air between the fibers.  This layer should consist of a shirt and pair of pants made from fleece, polypropylene, or wool.  You should never wear blue jeans.  Cotton holds moisture and loses its insulating properties when damp.  A friend of mine who ran cold weather survival classes said that based on his experience he wouldn’t take students on a cold weather trip who wore jeans or cotton.  As an option (one I prefer) you may want to add a vest.

The outer layer, pants and jacket should be water/wind resistant, but breathable to let perspiration evaporate.  It is best if this layer has a hood.

Wear a good pair of gloves or mittens and do not forget to cover your head.  In some circumstances, you can lose up to 50% of your body heat through your uncovered head and neck.  A fleece neck gaiter (like a collar) or facemask is necessary on very cold days.  Mittens, in general, are warmer than gloves, but offer you less dexterity.  Consider the type of activity you’ll be doing.  Personally, I like wool gloves with a removable waterproof outer shell.

Keep your feet warm with two pairs of socks and a good pair of boots.  This is a minimum for cold weather.  If you are in wet weather or snow, make sure your boots will repel moisture.

The reason that layering works is that it gives you the ability to control your body heat.  Layering gives you the flexibility to add or remove layers, depending on the weather and your activity.  If you are to warm, you will sweat and collect moisture in your clothes.  Layering also traps air between the layers providing additional insulation.

I am still a big believer in wool, there is a reason our ancestor depended on it. Untreated wool still has the fatty lanolin from the original animal and can be almost waterproof.  Even fine wools give you some protection.  Wool fibers are highly absorbent and can soak up around 20% of their weight in water before it starts to leak through.  Sailors and fishermen in extremely wet and cold climates have traditionally worn tightly woven sweaters of raw wool for their protection.  Wet wool will keep you warmer than other fabrics when wet, but you will still be cold until it dries.  The best thing is to stay dry and  avoid hypothermia.

Howard

 

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One Response to Hypothermia, How to Dress to Avoid It

  1. ke4sky says:

    The following is from Winter Annual Refresher Training we use with our volunteer CERT, Medical Reserve Corps and Ski Patrol.

    An important factor in any winter operations is hypothermia awareness, prevention of cold weather exposure injuries and prompt treatment of affected personnel.

    Prevention = COLD — Cover, Overexertion, Layers, Dry

    Cover.

    Wear a hat or other protective covering to prevent body heat from escaping from your head, face and neck. Cover your hands with mittens instead of gloves. Mittens are more effective than gloves because mittens keep your fingers in closer contact with one another.

    Overexertion.

    Avoid activities that cause you to sweat a lot. The combination of wet clothing and cold weather can cause you to lose body heat more quickly.

    Layers.

    Wear loose fitting, layered, lightweight clothing. Outer clothing made of tightly woven, water-repellent material is best for wind protection. Wool, silk or polypropylene inner layers hold body heat better than cotton does.

    Dry.

    Stay as dry as possible. Get out of wet clothing as soon as possible. Be especially careful to keep your hands and feet dry, as it’s easy for snow to get into mittens and boots.

    Winter driving safety.

    During cold-weather months, keep emergency supplies in your car in case you get stranded. Supplies should include several wool blankets (which are still warm when wet), matches, candles, a first-aid kit, dry or canned food, and a manual can opener. Travel with a cell phone if possible. If stranded, put everything you need in the car with you, huddle together and stay covered. Run the car for 10 minutes each hour to warm it up. Make sure a window is slightly open and the exhaust pipe isn’t covered with snow while the engine is running.

    Cold-water boating safety.

    Water doesn’t have to be extremely cold to cause hypothermia. Any water colder than body temperature causes heat loss. The following tips may increase your survival time in cold water, if you accidentally fall in:

    Wear your PFD. It enables you to float without using energy and provides some insulation. ALWAYS attach a utility knife, whistle, LED blinker and signal mirror to your PFD.

    Get out of the water if possible. Get out of the water as much as possible, such as climbing onto a capsized boat or grabbing onto a floating object.

    Don’t attempt to swim unless you’re close to safety. Unless a boat, another person or a life jacket is close by, stay put. Swimming uses up energy and shortens survival time. Position your body to minimize heat loss. Use the heat escape lessening position (HELP) to reduce heat loss while you wait for rescue assistance. Hold your knees to your chest to protect the trunk of your body. If you’re wearing a life jacket that turns your face down in this position, bring your legs tightly together, your arms to your sides and your head back.

    Huddle with others. If you’ve fallen into cold water with other people, keep warm by facing each other in a tight circle.

    Don’t remove clothing. While in the water, don’t remove clothing. Buckle, button and zip up your clothes. Cover your head if possible. The layer of water between your clothing and your body will help insulate you. Remove clothing only after you’re safely out of the water and can take measures to get dry and warm.

    The recommended treatment of hypothermia victims in the field is core rewarming to prevent post-rescue collapse.

    Handle victims gently. Limit movements to only those that are necessary. Don’t massage. Excessive, vigorous or jarring movements may trigger cardiac arrest.
    Move the person out of the cold into warm, dry location if possible. If unable to move indoors shield victm from cold and wind as much as possible.

    Remove wet clothing. Cut away clothing if necessary to avoid excessive movement.
    Cover victim with blankets. Use multiple layers of dry blankets or coats to warm the person. Cover the head also, leaving only the face exposed.

    Insulate the victim from cold ground. If outside, lay victim on the back on a blanket or other warm or insulating surface.

    Monitor breathing. Victims severe hypothermia appear unconscious, with no apparent signs of a pulse or breathing. If breathing has stopped or appears dangerously low or shallow, begin cardiopulmonary resuscitation (CPR) immediately.

    Share body heat. Lie next to victim, making skin-to-skin contact. Then cover both of your bodies with blankets.

    Provide warm beverages if victim is alert and safely able to swallow. Avoid alcohol or caffeinated beverages.

    Apply warm, dry compresses only to the neck, chest wall or groin, not to the extremties. Heat applied to arms and legs forces cold blood back toward the heart, lungs and brain, reducing core body temperature to drop and may induce cardicac arrest.

    Don’t apply direct heat. Don’t use hot water, a heating pad or a heating lamp to warm the person. The extreme heat can burn the skin or induce cardiac arrest.

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