by Ruby Bayan
Next to oxygen and water, warmth is the human body's vital requirement for survival. A core body temperature drop from the normal 37 degrees C (98.6 degrees F) can trigger a potentially fatal condition known as hypothermia, one of the leading causes of death in wilderness recreation.
The human body is designed to sustain a normal core temperature to keep the internal organs functioning efficiently. If the body is exposed to cold air, immersed in cold water, or soaked for an extended period of time, it involuntarily compensates, generating heat by shivering, and minimizing further heat loss by constricting blood flow to the extremities.
But if freezing conditions make the body unable to keep up with the heat loss, hypothermia sets in. Vital functions start to deteriorate, resulting in poor coordination, impaired judgement, loss of consciousness, and possible cardiac arrest.
Preventing Heat Loss
The body loses heat through several ways: sweating, inhalation of cold air, and exposure to water, cool air, strong wind, or a cold surface. One or a combination of these conditions, which are inevitable in most backpacking adventures and outdoor recreations, can lead to the onset of hypothermia, therefore, adequate knowledge on preventing heat loss is vital.
Remember that the thermal conductivity of water is 32 times greater than that of air, so exposure to cold water lowers the core body temperature more rapidly.
Here are some tips on how to prevent or minimize the loss of body heat:
- Wear breathable wool-blend clothing that wicks away moisture from the skin and remains warm even when wet. Cotton shirts and denim pants are warm only when dry; once wet, they lose their insulation properties.
- Layer clothing, and top with a weatherproof jacket that will ensure protection from cold winds and heavy rain or snow.
- Keep head, hands, and feet covered to avoid exposure to cold environments.
- Replace wet with dry clothing as soon as possible. Take off wet socks and underwear at the first opportunity.
- Breathe through a wool muffler to prevent inhalation of cold air.
- Seek shelter behind natural windbreakers, under improvised canopies, or in dug-up trenches.
- Build a fire.
- Share body warmth by huddling.
- Generate body heat by drinking warm sugary fluids, eating energy food like sweets, nuts, and cereal bars, and performing isometric exercises.
The first signs of hypothermia are shivering, skin numbness and poor coordination. As the body's temperature continues to drop, the victim begins to shiver violently, having difficulty talking and maintaining balance. Chattering teeth, fumbling, and stumbling are indicative of the detrimental cooling down of the body core.
Moderate hypothermia has set in when the victim stops shivering as muscles benumb and lock up. Mental dysfunction follows -- incoherence, irrational behavior, and sleepiness. Disoriented, oblivious, and half-awake, the victim becomes more susceptible to freezing.
Hypothermia is considered severe when the symptoms are rigidity, ice-cold skin, unconsciousness, and respiratory/cardiac failure. At this stage, the probability of death is high, therefore, immediate and proper rescue procedures have to be undertaken.
A hypothermia victim is seldom aware of the worsening condition at hand, therefore, care and treatment will have to be addressed by the victim's companions.
At the first sign of impending hypothermia:
If the victim is already shivering uncontrollably:
- Encourage the victim to generate body heat by drinking warm sweet fluids, eating energy food, and staying active.
- Prevent further heat loss by layering clothing, protecting all exposed areas of the body.
- Build a fire and huddle together to prevent a chilling companion from regressing into hypothermia.
If the victim is rigid and unconscious:
- Seek shelter (preferably inside a tent) as soon as possible.
- Replace all wet with dry and warm clothing, making sure to cover the head and all extremities.
- If the victim is still able to drink, give warm, sugary fluids to re-warm the body core.
- Prevent further heat loss by applying warmers close to the victim's "thoracic core", i.e., on the head, neck, chest, armpits, and groin. Remember that a hypothermia victim can become incoherent and irrational and may resist assistance; do what needs to be done to save the person.
- Skin-to-skin contact (against the chest or the back) with one or two other people inside a sleeping bag is also effective. Have the companions exhale warm breath towards the victim's mouth and nose -- this will minimize the victim's inhalation of cold air.
- Seek help and evacuate the victim to a medical facility as soon as possible. Handle the victim gently, preventing sudden movements or activity because a rush of cold blood from the extremities can shock the heart into ventricular fibrillation -- the leading cause of death in the initial rescue of hypothermic victims.
- Handle the victim very gently. Cut away wet clothing and wrap the victim in warm and dry blankets.
- Monitor vital signs. Perform CPR if no pulse is detected after two minutes. Victims of severe hypothermia seem to be dead. Do not assume death because it is possible that the body has lapsed into a hibernation state and can still be revived with proper medical attention.
- Seek help and rush the victim to the nearest medical facility.
The Outward Bound Backpacking Handbook, Glenn Randall Inc Outward Bound; Format: Paperback, 192pp.; ISBN: 1558219412; Publisher: Lyons Press, The; Pub. Date: January 2000
Wilderness Medicine: Beyond First Aid, William W. Forgey; Format: Paperback, 5th ed., 256pp.; ISBN: 076270490X; Publisher: Globe Pequot Press; Pub. Date: September 1999
Wilderness First Aid: When You Can't Call 911, Gilbert Preston; Format: Paperback, 128pp.; ISBN: 1560445793; Publisher: Falcon Publishing, Incorporated; Pub. Date: August 1997
Outdoor Survival Basics
What to Wear