The Cold Facts about Hypothermia

If you ever go to cold countries, you should undoubtedly have heard of Hypothermia. If you haven't, you should learn something about it. Your very own life may depend on knowing the information below:

Hypothermia is a condition marked by an abnormally low internal body temperature. It develops when body heat is lost faster than it can be replaced. Normal muscular and cerebral functions become impaired and death can follow if it becomes worse. This takes place below 96º F and lower.

Signs of hypothermia include confusion or sleepiness; slurred speech or shallow breathing; weak pulse or low blood pressure; stiffness in the arms or legs or poor control over body movements. Severe hypothermia can cause an irregular heartbeat, leading to heart failure and death.

Symptoms of Hypothermia

Shivering is typically the first sign of hypothermia. It eventually becomes uncontrollable. However with severe hypothermia, shivering stops. One of the key indicators that the victim has moved from mild/moderate hypothermia to severe hypothermia is that he/she is no longer shivering.

Behavior changes like complaining, difficulty in speaking, and uncoordinated movements. Victims will struggle to perform simple tasks like walking a straight line or zipping up their coat. With severe hypothermia, behavior changes from erratic to apathetic to unresponsive. Uncharacteristic behavior like inappropriate excitement or lethargy, poor judgment, and poor decision making are common.

Cold, pale and blue-gray skin due to constricting blood vessels. May develop into a coma, with dilated pupils making it difficult to determine if the victim is alive or dead.

How Heat is Lost from the Body

Convection: Heat is carried away from the body by currents of air or water. Wind chill is an example of convection.

Conduction: Transfer of heat between two contacting surfaces. Water conducts heat 25 times faster than air and steel is even faster than water. Generally conductive heat loss accounts for only about 2% of overall loss. However, with wet clothes the loss is increased 5 times.

Evaporation: Heat loss when water is removed from the body during sweating and respiration.

Radiation: The loss of radiated heat from a warm body to a surrounding colder environment. This is more significant on cold, cloudless nights. Factors important in radiant heat loss are the surface area and the temperature gradient.

It is important to recognize the strong connection between fluid levels, fluid loss, and heat loss. As the body moisture is lost through the various evaporative processes the overall circulating volume of water in the body is reduced, leading to dehydration. This decrease in fluid level makes the body more susceptible to hypothermia.

Field Treatment for Hypothermia

The basic principles of re-warming a hypothermic victim are to conserve the heat they have and to replace the body fuel they are burning up to generate that heat.

Reduce Heat Loss. Find shelter from the wind, and cold. This could be under a tree, in tent, or in a sleeping bag. If at all possible, get the victim off of the ground (a foam pad would be ideal). Remove any wet clothing and replace with layers of dry clothing, increased physical activity.

Add Fuel and Fluids. Keep a hypothermic person adequately hydrated and fueled. Give them warm, sweet liquids but NO coffee or tea - and NEVER ALCOHOL!
Alcohol - a vasodilator - increases peripheral heat loss

Caffeine - a diuretic - causes water loss increasing dehydration

Tobacco/nicotine - a vasoconstrictor, increases risk of frostbite
Provide Heat Source. Light a fire or a stove.

Seek Medical Attention as quickly as possible. Never leave a hypothermic victim alone.

Prevention of Hypothermia

Dress Appropriately. Wear clothing to keep the warmth. Avoid cotton!

Stay Dry - be aware that water comes from both the outside (environment) and the inside (perspiration). Stay out of the wind if possible.

Keep Your Body Burning. Stay hydrated, and eat foods like carbohydrates and proteins to provide energy.

Conserve Your Energy. Exhaustion leads to a quicker onset of hypothermia.

Summary

It's important to keep warm and dry during the cold, winter months. Dressing appropriately can make a big difference. Wear several loose, warm layers. Thick wool socks and a cap can combat winter's chills. At night, use extra blankets because hypothermia can develop during sleep. Thermal underwear are excellent for keeping the heat in your body.

Get plenty of rest. Fatigue makes you more vulnerable to subnormal heat and cold. Eat nutritious foods, and exercise moderately. Limit your alcohol intake because alcohol speeds up body heat loss.

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