Most animals are limited to the climate to which they have adapted. Animals which dwell in cold areas have long fur and protective deposits of fat. Desert animals hide from the sun and utilize very little water. Humans are the only animals whose range covers the planet, because humans adapt the environment to suit their needs and adapt themselves to their environment.
Humans must keep their bodies within a very narrow temperature range. If the body core temperature rises or falls a few degrees, a life threatening situation is at hand.
Heat is produced by the body as a waste product of metabolism. Excess heat is carried by the blood from the body core and dissipated through the skin. The skin is cooled by the evaporation of sweat. What happens to the body if the cooling systems breaks down?
This condition is caused by physical exertion in a hot environment. It is not limited to persons in poor physical condition. The blood vessels in the skin become so dilated in an attempt to rid the body of heat that the brain and other vital organs are denied an adequate supply. This is not a life threatening situation, but if ignored it can escalate into one.
The victim is faint, nauseous, and dizzy. Vomiting, headache, restlessness, or loss of consciousness may occur. It is important to note that the victim's skin is pale and the skin temperature is close to normal. Sweating may be normal or profuse.
When this occurs, the victim should be moved into the shade and given fluids and electrolyte replacement (never give an unconscious person anything to eat or drink). After a few minutes rest and adequate water, the victim is usually fully recovered.
Heat stroke is another matter entirely. Heat stroke is a life threatening situation, and it must be treated immediately to avoid brain damage or death.
Normally the sweating rate decreases while working in the heat. The sweat glands can apparently become exhausted and "close down" , particularly if the victim is not given some relief from sweating by cooling off at night or by some other means.
The sweating process and other heat regulatory mechanisms stop working altogether. This occurs suddenly. The victim becomes confused, uncoordinated, delirious or unconscious. The body temperature is above normal, the skin is hot, and the victim does not sweat. The skin may be bright red.
Untreated cases lead to death due to brain damage. This is a true medical emergency. The body must be cooled as quickly as possible. If water is available, the victim should be immersed totally in tepid, not cold, water. Otherwise the victim should be cooled with cloth soaked with alcohol or water and fanned. Ice packs are not the best solution, as they may lead to tissue damage. The limbs should be massaged to encourage blood circulation and thus increase cooling of the vital organs.
Treatment may be halted when the body temperature reaches 102 degrees. The victim should be watched carefully to avoid a reoccurrence. Aspirin may be harmful and should not be given. Medical help should be obtained as soon as possible. If the person's temperature comes down, and they remain in a coma, brain damage is probable and evacuation is vital.
Many parties in the desert require that each member of the party carry a specially marked quart of water which is saved in case it is needed to cool a heat stroke victim.
A person with heat exhaustion may slip into heat stroke without warning. There is no clear delineation between serious heat exhaustion and the onset of heat stroke. Treat all heat related ailments immediately.
Recently a heretofore rare condition has been observed among hikers in the desert. This is water intoxication. If a person drinks too much water without eating, the cells of the brain can swell and cause symptoms of nausea or drunkenness. A person who drinks and eats normally while hiking will not be faced with this situation. It occurs when people who are justifiably worried about hiking in the heat drink an excessive amount of water without intaking food. Under normal conditions, excess water will be eliminated form the body via sweat or urine. If the electrolyte balance is disturbed or the body is carbohydrate starved, water intoxication may result. Treatment consists of giving the person rest and something to eat.
Muscle cramps may result from inadequate water or salt. Cramps can be stopped by stretching the muscle. Heat cramps may be indicative of inadequate salt intake. Remember that salt should not be taken unless there is plenty of water to go along with it.
Prickly heat is not serious, but it is uncomfortable. This occurs due to obstruction and inflammation of the sweat glands. Most creams and ointments as well as rubbing clothing aggravate the situation. The treatment is removal from the heat.
Heat injuries can be avoided by intake of enough fluid and salt. Preventive measures include resting in the shade during the hottest part of the day, wearing clothes to conserve the body's sweat, and wearing a hat. If the humidity is high, strenuous activity in the heat should be avoided altogether. Plastic sweat suits utilized for fast "weight" loss are not safe under extremely hot conditions.
It would seem that problems with the cold would be the last thing to worry about in the desert. However, in most deserts loss of radiation heat at night through the clear, arid air results in very cold nighttime temperatures. Nighttime temperatures can be 40 to 50 degrees lower than daytime temperatures.
During the summer, this is usually not a consideration. Nighttime temperatures should range from 70 to 100 degrees. During the spring and fall, temperatures can fall into the dangerous range. During the winter, they will. The temperature does not have to be extremely cold if conditions are wet and windy. Often hypothermia occurs between 32 and 60 degrees. Hypothermia, commonly known as "exposure" or "freezing to death", causes up to 85% of deaths occurring among outdoors persons.
Metabolic body heat must be dissipated in hot conditions. In cold conditions, body heat must be maintained. The body loses heat by many of the same routes that it gains heat:
Prevention of hypothermia requires the reduction of loss of body heat. Since body heat is produced as a byproduct of exercise, it would seem that exercise would keep one warm. This is true, but the body utilizes food for energy, and if food is limited, if the victim becomes exhausted and weak, this system can break down. When there is no more food for energy, the body heating system runs out of fuel. This is the beginning of hypothermia.
One way to prevent hypothermia is to provide a constant intake of calories when the body is engaged in hard exercise. Small, high calorie snacks over a period of time are more effective than a few large meals. One may note that when water is limited, food intake should be reduced or eliminated to avoid dehydration. It is a moot point whether one should eat and suffer loss of body water or not eat and suffer hypothermia. This is a decision to be made according to the circumstances. No one said survival was easy.
Prevention of loss of body heat is important in prevention of hypothermia. We shall consider the four sources of heat loss:
Wearing clothing or utilizing a blanket or sleeping bag will reduce this source of heat loss. An unprotected head may lose up to 50% of the body's heat to the air. Always wear a hat, for heat and for cold.
Contact with anything cooler than the body will rob the body of heat. During the heat of the day this is to be desired. During the cool of night, it is to be avoided. Avoid sitting or lying on cold ground. Use padding under the body.
Clothing will retain a layer of warm air close to the body, and reduce the heat lost to convection. Wind will carry this heat away at a fast rate. Some sort of wind-proof clothing or emergency shelter material, such as plastic or a metallic survival blanket, should be carried.
Experienced outdoors persons avoid excess sweating even in a non survival situation. When the clothing becomes saturated with sweat, it is much less protective. Utilize the "layer" system of clothing. Rather than wearing one thin shirt and a heavy coat, wear a thin shirt, a thin long sleeve shirt, a thicker long sleeve shirt, and a windbreaker. This allows flexibility as the temperature fluctuates, and there is less chance of overdressing and sweating to excess while exercising and thus allowing the clothing to become damp. Wool is a good survival material, since it stays warmer when wet than other fabrics. Synthetic materials such as polypropylene-type fabrics and pile fabrics also stay warm when wet.
A fire is a good way to stay warm in a survival situation, but one should not rely on this as a sole means of staying warm. Extra clothing and emergency shelter material should always be carried. If the weather is wet and windy, the effect of a fire is drastically reduced, assuming one can be maintained in the first place. Wood is often at a premium in the desert, and it will be difficult to find enough to keep a fire going all night. A small fire is more efficient than a large one, since a person can sit closer to it. A small fire is also easier to maintain, requiring fewer searches for wood. Sitting between two or three small fires can be most effective.
As the body core temperature drops, the following symptoms may become apparent:
98-95: Feeling chilly; numb skin; incoordination, especially in the hands; shivering.
95-93: Obvious incoordination and weakness; stumbling; slow pace; mild confusion; apathy.
93-90: Gross incoordination; frequent stumbling; inability to use hands; mental sluggishness; slow thought and speech; forgetfulness.
90-86: Stops shivering; severe incoordination; stiff and unable to walk or stand; incoherent; confused; irrational, .
86-82: Rigid muscles; semiconscious; dilation of pupils; cannot always find pulse or heart beat.
82-78: Unconsciousness; death due to heart failure.
A thermometer will not register body temperatures this low. Symptoms will help ascertain the severity of hypothermia.
When one member of the party displays symptoms of hypothermia, the party should stop and treat this person, unless there is obvious danger in the area or some warm shelter such as a house is very close by.
A shelter should be set up if this is possible. Wet body clothing should be removed and replaced with warm, dry clothes. It may be necessary to build a fire to dry clothing and provide warmth. The victim must be warmed from outside sources; when the body is no longer producing heat, placing the body in a sleeping bag or other insulative materials will do no more good than placing a rock within. A most effective method is person to person contact. Warm stones or bottles full of warm water may be used if care is taken to avoid burning the skin.
Hypothermia victims are prone to frostbite. Hands, feet, and exposed areas such as ears or nose should be protected, particularly in damp or snowy conditions.
The best way to treat hypothermia is to prevent it. Extra clothing should always be carried to allow for sudden changes in the weather. Some sort of emergency shelter should be in any survival kit. The party should be alert for signs of hypothermia if conditions are cool, wet, and windy. A person under the influence of hypothermia does not think clearly, and the victim may not be aware that he or she is in trouble and deny the very idea.
Chapter nine Please
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