Hypothermia is a condition of abnormally low body-core temperature. The body's surface and extremities may drop several degrees in temperature without serious difficulty. But when the temperature of the deep areas of the body begin to be affected, hypothermia occurs. The word comes from two roots--hypo meaning below and thermia derived from the word for heat.
Hypothermia is a condition that sneaks up on the unwary. Its onset is sometimes so gradual as to be unnoticed by anyone around the victim. And, because of its slowing affect on mental processes, victims themselves are almost assured of failure in noticing symptoms. The frightening thing is that from the time symptoms of moderate to severe hypothermia are noted by an observer, the victim may be dead in as short a time as 2 to 4 hours.
Hypothermia's Sequence of Symptoms
As cold removes heat from the body, the peripheral circulation (that near the skin surface) begins to be reduced by blood vessel constriction. So does that in the fingers and toes. In an effort to maintain the body's core temperature at normal levels, blood is held away from the chilled body surface. Often an early symptom of this shift will be a numbness in one or another finger and a feeling of chilliness over the body. Shivering initially begins. This is the body's effort to produce additional heat through exercise and enhanced oxidation of food materials. As chilling progresses, it becomes difficult or impossible to carry out fine muscle movements, such as working with the fingers. The chemical reactions enabling finger flexing simply cease to be effective. Shivering becomes more intense as the body attempts to offset cooling. Progressive chilling finally results in heat loss for which the body cannot compensate. The temperature of deep circulation begins to fall. Fatigue sets in, reducing the heat-producing shivering. The body's core temperature drops still more. As chilling continues and the body cools, the chemical reactions that oxidize food and produce heat slow down. Thus, heat is produced less rapidly and the body cools even more quickly. An increasingly rapid interacting heat loss pattern is now initiated. As the body cools, it is even less able to chemically heat itself so it cools even more rapidly. Still less heat is produced by the slowing metabolism, and the body's rate of cooling steepens. Thinking becomes sluggish as the blood circulating through the brain chills it. Ability to perform mental tasks is affected. Speech becomes slurred and progressively incoherent. Large muscle function is affected, causing a stiff legged stumbling gait. The victim has a glazed expression.
Shivering has, in the meantime, been producing metabolic products. Lactic acid, normally carried away by increased circulation through the muscles, tends to accumulate, producing a feeling of intense exhaustion and often inducing pain and cramps. Plodding forward the victim finally is no longer able to remain upright and falls forward. Consciousness wanes and waxes. Losing consciousness completely, the hypothermic person gradually passes into a coma. Heart action and respiration become erratic, with cardiac arrest or fibrillation developing. Fluid fills the lungs, and a froth pink with blood may appear at the nose and mouth from pulmonary edema. Death follows quickly.
It is important to quickly treat the ailing person, Victims have died because companions did not take the situation seriously or react quickly enough.
Hypothermia is easiest to treat in the early stages. Keep a careful eye on members of the party, especially if they are wet and in windy conditions. At the first sign of intense shivering, lapses in memory or uncoordinated movement, take action.
Stop traveling and establish camp. If heat loss exceeds the body's ability to restore or maintain normal core temperature, death from hypothermia is guaranteed in time. Build a fire and if possible change wet clothes for dry. Provide hot drinks even if only hot water is available. At this point the victimÕs body is still able to restore normal function.
If lapses in memory, slurred speech, and staggering gait have developed, the situation may have progressed to critical. Dry clothing, shelter, and a warm fire are still mandatory. But the victim's own metabolic processes may no longer be able to restore normal core temperature. If lapses in consciousness have developed, this is definitely the case. Encourage them to walk. Be sure that their clothing is dry. Provide them with hot drinks. A severely hypothermic person may be literally killed in short order by inappropriate treatment. Above all, NEVER GIVE A HYPOTHERMIC PERSON ALCOHOLIC BEVERAGES! Two things may happen. If the hypothermia has been induced by anything other than cold water immersion, there is usually a fairly prolonged period of shivering. Remember the earlier comment made regarding lactic acid buildup in muscle tissues by this action. There is a large component of lactic acid waiting in reserve.
Second, the body has tried to limit heat loss by reducing to an absolute minimum any blood flow near the cold surface of the body. It has done this by peripheral vasoconstriction--the blood vessels near the skin surface have been reduced in diameter. Blood flow is concentrated near the core of the body. Because of this, the outer layers of body tissue are quite cold. Alcohol taken into the body causes almost immediate vasodilation. Those narrowed surface vessels suddenly open wide permitting the warm blood from the body's core to surge into the cold tissue near the surface, where its temperature drops precipitously. As this blood rushes toward the surface, it also picks up large quantities of the lactic acid produced in shivering. This changes it chemically, making the circulating blood more acidic. In effect, what is happening is that suddenly a mass of severely chilled, abnormally acidic blood is now rushing through the circulatory system toward the heart. When it gets there it is very likely to cause the heart to immediately stop beating regularly- to fibrillate. This uncoordinated quivering of the heart muscle does little or nothing to keep blood moving normally. Or, the cold acidic blood that reaches the heart may simply cause heart action to stop completely. In either case, without immediate and heroic treatment, death is only moments away. Remember, NEVER give a hypothermic person ANY alcoholic beverage!
Handle the victim with great gentleness. Rough handling as clothing is being removed or as they are being transported, may cause cardiac arrythmia and sudden death. Massaging or rubbing the skin brings blood to the surface and can do likewise.
In general, field treatment involves the following steps.
People unfamiliar with desert conditions often exhibit one of two extreme responses. They are either unrealistically frightened by the desert or show a cavalier disregard for the potential hazards.
While it should be apparent that water is a serious limiting factor, newcomers often are entirely unaware of the quantities necessary to sustain life. General environmental dryness coupled with extreme heat during much of the year combine to place severe stress on the survivor.
Deserts are often characterized as harsh, demanding, and dangerous by those who are unfamiliar with them. Yet, globally many people live and thrive in desert country. Generally speaking, there is no reason why a trained person should not be able to survive limited, unforeseen stays there. However, there are some desert areas of the world where a victim will find it almost impossible to sustain life for long. There simply are not ways to cope with all the extremes possible in the environment.
Anytime travel off main roads or flights over desert country is planned, it is advisable to carry plenty of water. Plan to carry at least a gallon of water per person on backroad trips.
It is a good idea when traveling remote desert areas to have at least two vehicles. If one breaks down, the other may be the only reliable source of rescue. At the very least, spare parts and tools should be carried.
Drivers in desert areas learn quickly that a vehicle can easily become stuck in sand in the same way it would in loose snow. Avoid dry, light-colored, sandy areas. These sands are often very loose, and the car will immediately sink to its hubs.
If this should occur, there are several ways to get out. Some people carry 2 feet wide by 12 feet long strips of closely woven wire mesh, heavy carpet, or canvas. These can be placed under the drive wheels and used to assist in gaining traction.
Tire pressure may also be reduced by about one-half the normal amount. This will allow the tires to mush down and spread out, giving additional pulling power. But do not lower the pressure below this. Tire damage is likely to result and it will be impossible to continue to drive after getting out of the sand. Special compressed gas tire refill cylinders or spark-plug type tire pumps work well to reinflate a tire, either after a repair or following the above procedure.
DO NOT RATION DRINKING WATER. In spite of various fictional accounts of travelers severely limiting water intake and thus living through a dangerous desert experience, water should not be rationed. Emphasize rationing sweat, not water.
As the surface of the body rises above a certain point in temperature, sensors cause pores to open and sweat glands to produce perspiration. This slightly salty solution flows out on the skin surface and acts as an evaporative coolant.
The more heat stress to which the body is subjected, the faster flows the perspiration. Under extreme conditions sweat may be produced at a rate of 2 quarts an hour. Obviously, this water must come from somewhere. Its source is food and drinking water. The body is literally drying itself out in order to facilitate cooling and to prevent the core temperature from rising too high. But this water is coming from a limited reservoir--the body.
A widely held dangerous myth is that the human body will develop a certain capacity to withstand periods of dehydration over time -- that it will require less water after it becomes accustomed to the heat. This is just not true. Studies indicate that, although psychological thirst may be reduced, physiological thirst is not affected. Given the same amount of physical activity, a person who has spent an extended period under desert conditions will physiologically require the same amount of drinking water as one who has not.
The four variables that affect water requirements are (1) air temperature, (2) exercise, (3) food intake, and (4) health. As temperature and exercise increase, so do water requirements. Ingestion of food also causes the body to require additional water as a means for digestion and assimilation. Furthermore, various pathological conditions may increase the body's water requirements.
Rationing drinking water is counterproductive. In general, it is safe to say that under desert conditions you should drink when you are thirsty whether or not you have adequate water. When you scrimp on water you soon reduce the bodyÕs efficiency and likely reduce survival chances.
Loss of efficiency begins with relatively slight water losses. For example, a 2 1/2 percent body weight loss (about 1 1/2 quarts) will result in a 50 percent loss in efficiency.
Efforts to conserve body moisture include avoidance of wind. The drying effect of the wind can be profound. Shelter formed either from brush fastened into a crude windbreak or supplied by existing rocks or vegetation may assist.
Avoid sitting or lying on the ground if it has been in the direct sun. An improvised platform a foot off the ground is ideal, but a 6-inch elevation may reduce the temperature by 30 or more degrees. The surface temperature of dark-colored rocks may reach as high a 160 degrees F!
If you are exhausted and must sit or lie down in a sandy area, first scrape away at least 3 inches of dirt or sand. This will reduce the surface temperature of your seat by up to 30 degrees.
Keep your mouth closed. Breathe only through the nose. Mouth breathing dries the oral cavity and the mucous membranes of the throat quickly and will greatly enhance the sensation of thirst. Because of this, smoking is not advisable. It tends to promote mouth breathing, and the inhaled smoke is often very warm and will further dehydrate the mouth and throat. Strictly avoid alcohol. Alcohol accelerates dehydration. The process of conversion of alcohol to sugar in the body requires water. In effect, drinking alcohol is like eating. If water is a critical problem, DON'T EAT.
Streams, rivers, lakes and springs are all likely and usual places to look for water during warm weather. Since water accumulations most often occur where the land surface lies below the water table known as the zone of saturation, a dry stream bed may be a successful spot to dig for water. Digging on the outside of a bend is best. The current of the stream is most rapid at the outside of the curve, with eddies and backcurrents allowing sand and other sediment to accumulate on the inside of the curve. The result is that the bed is deepest and therefore closest to the water table where the scouring action of the current was greatest. Since this is also the most depressed area, it is the last area to hold water as the stream receded. There may be residual water quite near the surface. If digging uncovers damp sand, keep it up until water begins to seep into the hole. Allow it to fill, carefully scoop it out, and purify it.
Since cliffs often intersect the water table, springs or seeps may be found there. Often identified in desert country by the obviously greener vegetation growing there, these moist oases may be visible several miles distant. Disappointingly, these spots may only be damp on close examination. Dig back into the wet area. The flow may be increased or at least encouraged to drip occasionally. Place a container under the drips and you will be surprised to see how quickly the water accumulates. And, if the only thing you have to catch the water in is your dirty old sweaty boot or shoe, remember "Beggars can't be choosers." Use it anyway. With a serious water shortage, thirst is probably far more important than an incipient case of athlete's mouth. (Use water purifying chemicals in your shoe.)
Rainwater that has collected in depressions in rock surfaces should be pure since it has not normally contacted human disease organisms. Still, it is recommended that it be purified to be absolutely certain. But in a "forever situation," this source is one of the least likely to be contaminated.
While there may be pure sources of water in the outdooors, it is safest to assume that all water is contaminated. Regardless of whether you have drunk from a particular source a hundred times with no ill effexcts, do not assume it to be safe under survival conditions. It is one thing to develop gastrointestinal problems when you can merely pack up and drive home. It is entirely another when you are stranded. Always carry water purification tablets in your vehicle "survival kit" whenever you travel.
Cacti are among the best sources of water in an arid region. Ripe cactus fruit is largely water and is also pleasant to eat. It goes without saying that cactus plants should be handled with great care, preferably with gloved hands or using a layer of cloth to protect the hands. The red fruit of the prickly pear cactus has white spots or slightly fuzzy appearing areas on the surface made up of almost microscopic, pointed hairs. These stick in the skin and feel like small fibers of spun glass or steel splinters. Pick them with great care and then pare them before utililizing them. The inner pulp is juicy, sweet, and filled with seeds of about the right size to get stuck between your teeth.
The fleshy pads of the prickly pear cactus, handled with care to avoid the sharp spines, may be skinned or the spines burned off. The pulp, although not sweet, is moist and can alleviate thirst.
Yucca is a plant that occurs in deserts of various parts of the world. Its fruit, when ripe, is also moist and may help to slake thirst.
The agave or century plant is another source of moisture. Both the stalk and the fruit can be used for this purpose.
In some desert areas, the barrel cacus may be a source of potable water. The top is carefully cut out, exposing the internal white pulp. The exterior of the cactus is very tough and covered with overlapping long sharp spines, so that a stout knife with a blade at least 4 inches long will be a great help. Or a hatchet will do nicely.
Cut out chunks of the pulp and place in a piece of thin cloth and crush to remove water. Or the pulp may be pounded down inside the cactus itself to permit water to accumulate. However, the easiest way is to simply cut out chunks of the pulp, chew them, suck out the water, and spit out the remaining fibrous mass.
The taste will vary from location to location. The author's experience is that is it is much like gritty, diluted aspirin tablets. The grit may be from microscopic cell inclusions called crystoliths. A bit like sand, they are distracting but not harmful. A large cactus may produce two quarts of water.
Since it takes up to 200 years for a barrel cactus to mature, disturb them only in the direst of circumstances.
As temperatures fall during the evening, condensation in the form of dew may appear on cool surfaces such as car tops and hoods, aircraft surfaces, and even on vegetation. This may be mopped up with clothing and wrung out into a container. Surprising quantities may be obtained in this manner. Water vapor condenses out of the air because the surface of the metal or vegetation is at a lower temperature. Thus, the air at the cool surface reaches its "dew point" and moisture begins to appear as visible drops. The air mass represents a huge supply of water and, even though you may mop up all night, as long as the temperature differential between the air and the surface is great enough, the dew will continue to form.
Rain itself may provide a significant source of pure water. Especially in intense downpours (as sometimes happpens in desert areas), it is possible to collect several gallons of water. Try to increase the collecting surface. A raincoat, poncho, or even an ordinary shirt or coat may be arranged to permit runoff--the funneling of the accumulating rain into a container. If the material is not waterproof or repellant, it will still act to sluice off the water if it is arranged at a steep angle.
All animals require water to some extent. Most animals must have some source of liquid water. Be alert to birds, especially in the early morning or late afternoon and evening. Quail and doves, as well as other birds, often fly toward water at these times and their flight patterns may help locate drinking water. Sometimes birds may be seen circling a water source or their chirping and singing may give away its location. Game trails made by deer, antelope, cattle or other animals often lead to water.
Plant indicators of moisture include cottonwoods, willows, tamarisk, cattail, sedges and arrow weed. However, as mentioned above, water in these locations may be at some depth and require much energy to obtain.
Water may be made safe to drink by heat, chemicals or specific filtration methods. The best method is boiling, since all disease organisms are killed this way, although the newer filtration methods should also successfully remove bacteria and even some viruses.
Water should be brought to a rolling boil for at least 2 minutes and preferably 10. Add 1 minute for every thousand feet above sea level. So, at 5000 feet elevation, the water should be boiled 2 minutes for the basic treatment, plus 5 minutes for altitude compensation. The total boiling time would then be a minimum of 7 or a maximum of 15 minutes.
Halazone tablets [P-(N, N Dichlorosulfamoyl) benzoic acid], iodine tablets (tetraglycine hydroperiodide), tincture of iodine and bleach can all effectively purify water. However, in tropical areas where amoebic dysentery is found, the only guaranteed methods are boiling and special filters.