Hypothermia – The Need for Effective Outdoor Clothing
Hypothermia is caused by extended exposure to cold temperatures or a cool, damp environment.
It is defined as a body core temperature less than 35° Celsius. Decreased consciousness occurs when the core temperature falls to approximately 32 to 30°C.
A normal body temperature is 37°C so it’s not that far to 35° and below.
Unlike warm blooded animals that have a layer of hair or blubber to keep them warm, humans need an extra layer of clothing to keep them warm when the temperature drops significantly. Without that extra layer of clothing, more heat escapes from the body than it can produce.
If too much heat escapes, the result is hypothermia. Heart failure is the usual cause of death when the core temperature cools to below 30°C.
Inadequate outdoor clothing and neglecting to cover your head, hands and feet during cold weather can also cause the onset of hypothermia.
It must be remembered that a lot of body heat is lost through the head.
Hypothermia can happen not just in cold winter weather, when you expect low temperatures or wind chill factors, but also under ‘warmer’ conditions as well. A rain shower that soaks you to the skin on a cool day can lead to hypothermia, if you don’t get to warm up or dry off.
Any contact with cold water, may cause hypothermia to develop. This may happen within a few minutes of exposure to cold water or it may take several hours, it depends on the water temperature.
Any water that's colder than body temperature will cause heat loss. Water that's colder than 21° C can quickly start the onset of hypothermia.
The body loses heat to the water about 30 times faster than to air. When the water evaporates, it further cools the skin, dropping the body’s temperature.
A wind blowing over the wet parts of the body can dramatically increase evaporation and cooling.
Recognising the early signs and symptoms of hypothermia is important in any survival situation, although it must be stressed that this condition usually comes on gradually.
Common signs to look for are shivering, which is the body's attempt to generate heat through muscle activity, and the "umbles" - stumbles, mumbles, fumbles and grumbles.
These mannerisms may be the result of changes in motor coordination and levels of consciousness brought on by hypothermia.
Other signs and symptoms of hypothermia may include:
- Slurred speech
- Unusually reduced rate of breathing
- Cold, skin pallor
- Fatigue, lethargy or apathy
Wearing protective clothing and taking other precautions can ensure that the body temperature does not drop to dangerous levels.
It is important to be aware of local conditions and monitor any approaching weather.
The best approach to being cold and wet is to move indoors and get warm and dry early - before you encounter serious hypothermia.
There is some simple advice for those who may be exposed to cold and or wet conditions:
Using the simple acronym COLD.
C for Cover.
Wear something on the head, such as a balaclava or thick insulating hat to prevent body heat from escaping from the head, face and neck.
Hands should be covered with mittens instead of gloves. Although mittens are less practical than gloves they help to retain heat by keeping the fingers in closer contact with one another.
O for Overexertion.
Any activities that would cause excessive sweating should be avoided. The combination of wet clothing and cold weather can give a person chills.
L for Layers.
Loose-fitting, layered, lightweight clothing should be worn. Garments made of tightly woven, water repellent material are best for wind protection.
Wool, silk or polypropylene inner layers retain more body heat than cotton.
D for Dry.
Stay as dry as possible. In the winter, pay special attention to places where snow or water can enter, such as in loose mittens or boots.
When any professional is seen in the media in extreme conditions they always have the very best in outdoor clothing and outdoor survival equipment.
Why should you be any different?
Never try to save money on clothing or sleeping bags, if you can afford high quality.
Remember it is YOUR body that they are protecting.