Hypothermia

Winter is a good time to look at the subject of hypothermia, but winter isn’t the only time that hypothermia is a concern in Colorado.  Snow has fallen in the state in every month of the year.

Residents and tourists engage in hiking and other outdoor activities during every part of the year.  Weather conditions can change rapidly in Colorado.  Each year we have someone who is caught in a rainstorm or a snow storm unprepared and dies.  With that introduction, let’s look at the way hypothermia sneaks up and how it can kill and what to do to defend against it.

Hypothermia

Stage 1: Exposure and Exhaustion

The moment that your body can’t produce enough heat to keep up with heat loss to the environment, you are in a state of exposure.  Typically two things happen:

1. You start to move around or exercise to keep warm.

2. Your body makes involuntary changes in blood flow to protect vital organs.  Eventually you begin to shiver as the body tries to compensate for the heat loss.  Energy reserves begin to be drained at an ever increasing rate.

How rapidly the onset of exposure occurs depends on the physical condition you are in, how much you have already exercised, what kind of clothing you are wearing, whether or not you are wet, and if you are hydrated and have high energy food to eat.

Stage 2: Hypothermia

If exposure continues, your reserves of energy will become depleted.  At this point two things happen:

1. Brain function becomes impaired with judgment and power of reasoning diminishing.

2. Hands stop functioning and appendages may start to lose feeling with reduced circulation.  Speech becomes difficult and slurred.

This is the onset of full blown hypothermia.  Your body core temperature will continue to drop and when it gets to a temperature of 92ºF to 86ºF, you will have reached sever hypothermia, which is immediately life threatening.

People often associate hypothermia with extremely low temperatures when in actuality most cases occur between 50ºF and 30ºF.  Many outdoorsmen have a hard time believing that such temperatures are dangerous, which can prove fatal.

Defenses Against Hypothermia

1. Hypothermia preparedness should be first on your mind before you begin any trek.  Make sure you are over prepared even if you only plan on being out for a few hours.  Take essentials in a day pack to get you through at least one night on the trail.  Energy bars, plenty of water (hydration packs are great), extra clothing, a space blanket, wool socks, a first aid kit, and a means to make a fire are the bare minimum.

2. Stay dry.  Wet clothing loses 90% of its insulating capability.  Wool is the best material even when wet.  It also wicks moisture away from the body.

3. Get out of the wind.  Seek shelter from the wind if you don’t have the proper clothes to put on.  Even a slight breeze on your bare skin drastically increases convective heat loss.  If you are wet and in the wind, you have compounded the problem.

4. Understand how you lose heat. There are four ways that the body loses heat:

• Radiation – Your body is constantly radiating heat and the top of your head loses heat the fastest.

• Conduction – If your body is in contact with a surface or a liquid that is cooler than your skin, you will conduct heat to the cooler surface or liquid.

• Convection – Air flowing over your body drags warm air you have trapped around you away from the surface of your skin.

• Evaporation – Sweat or water on your skin takes heat with it when it evaporates.  50ºF water is bitterly cold and can quickly lead to hypothermia.

5. Avoid or terminate exposure.  If you did not come prepared for cold conditions, terminate the exposure.  Don’t continue the activity you had set out to accomplish such as the hike, the climb, the fishing or whatever you had planned.  It is not brave or wise, but foolish and could end up in a disaster for you or someone in your party.

• Get out of the rain, snow or wind as soon as possible.  Concentrate on making or finding shelter.

• Build a fire in a safe location near your shelter.

6. Persistent or violent shivering is a sign of clear and present danger of hypothermia setting in.  Make camp quickly before it becomes impossible during the later stages of hypothermia.

7. Don’t wait until you are exhausted to stop and prepare to camp.  If you delay, you may not have the energy reserves to properly prepare shelter or a fire.  Hypothermia is seductive, you may feel fine one minute and in the next you can’t think clearly or find the strength to do what is needed for survival.  When this happens, your body’s ability to produce heat drops by 50% or greater.  Now you are in a critical life threatening situation.

8. Stay hydrated.  Dehydration impairs the body’s ability to regulate body heat and metabolism and aids exposure leading to hypothermia.

9. Hypothermia awareness is another line of defense.  Know the signs and watch for them.  They are:

• Shivering uncontrollably.

• Difficulty speaking or slurred speech.

• Difficulty using your hands or general mobility.

• Difficulty thinking, incoherent thoughts or delirium, memory lapses.

• Drowsiness (this is the hand of death on your shoulder).

• Staggering and uneven gait.

• Exhaustion and the inability to get up after a rest and continue moving.

10. Treat hypothermic conditions immediately. Believe the symptoms in you or someone else. Don’t be in denial or you or a member of your party may die. Don’t be talked out of it by someone else but demand treatment. Take the following actions:

• Get the victim out of the exposed conditions (wind, rain, snow, etc.).

• Get out of wet clothing.

• For a mildly impaired person, give them something warm to drink and get them into warm, dry clothing or a sleeping bag or a space blanket.  Warm canteens or rocks well wrapped and placed against the victim will speed recovery.

• In severe cases where the patient is semi-conscious, leave them stripped and place them in a space blanket or sleeping bag with another person.  Remember what I said about conduction — it works to warm up a cold body, too.  Skin against skin is the most effective way to warm up the victim or to mutually stay warm.

• Build a fire in a safe location near your camp/shelter.  It is typically warmer under a tree and tree limbs can be used to make a shelter to reflect heat back at you and keep the wind off of you.  A cleft in the rock or a cave can also make good shelter.

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