Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

See all posts »

The Desert and Desert Survival 2

TEXT SIZE: A A A
This is the fourth post based upon educational sessions and syllabus material presented at the Wilderness Medical Society Annual Meeting & 25th Anniversary held in Snowmass, Colorado from July 25-30, 2008. This post continues the discussion about the desert and desert survival, based upon the extensive knowledge of Dr. Edward J. (“Mel”) Otten, who is Professor of Emergency Medicine and Pediatrics, and Director of the Division of Toxinology at the University of Cincinnati.

All desert flora and fauna have one guiding principle for survival, which is to conserve water. The ground surface of the desert has the highest temperature because of the direct effect of solar heat and wind. Therefore, during the hottest times of the day, most animals are either below the surface, in underground burrows, or above the surface in available vegetation, cacti, trees, or shrubs. Most animals forage from dusk until dawn, when temperatures are cooler. Some mammals, such as kangaroo rats, never drink, but obtain necessary water through plant seeds. Plants have evolved a number of survival adaptations to maintain water, including stomata which are closed during the day and crassulacean acid metabolism (CAM) photosynthesis, which allows for accumulation of carbon compounds at night via the dark reaction . Other adaptations include stem photosynthesis in plants without leaves, thick cuticles, water storage tissues, and widespread shallow root systems. They also have evolved a variety of defense mechanisms, such as production of toxic compounds that act as herbicides to others plants and the formation of needles, spines and thorns that dissuade browsing animals. Obviously humans are not ,able to evolve these physiological changes, but must rely on behavior, technology andother adaptations to mimic the methods used by indigenous desert dwellers.

All things being equal, preparation improves the likelihood of survival. However, things are never equal so luck is probably the most important factor. The controllable factors are mental and physical conditioning, clothing, survival kit adequacy and survival skills. These may allow one to survive even in the most extreme conditions.

Mental preparation is key to any survival situation. The “will to survive” has been shown to be the most important factor in the outcome of a number of situations. Knowledge of the terrain features, weather, animal and plant life, and potential hazards should all be studied prior to travel to a desert area. Not only does this increase one’s chances for survival, but enhances enjoyment of the desert environment. Practical experience in finding water and food, navigation, and constructing shelters is more valuable than reading about it. Time spent in attending a course on survival in general or desert survival in particular may be invaluable if one is later in a true survival situation.

Physical conditioning and acclimatization are as important for desert travel as for mountaineering. Desert travel is difficult under most circumstances. The terrain is rough and may include sand dunes, sharp loose rock, flash floods, steep grades, and hot surfaces. Leg conditioning helps prevent the ankle and knee injuries that can force a survival situation in a harsh climate. Acclimatization involves three well described physiological adaptations and usually requires 10 to 14 days in a hot environment. These adaptations are an increase in the volume of sweat and number of active sweat glands; a decrease in concentration of electrolytes in sweat, and sweating at a lower body temperature. These can be induced before arriving in a hot climate by the use of a sauna or vigorous exercise to raise body temperature.

Clothing selection for desert travel is somewhat different than for most other wilderness activities. The less exposed skin, the better. While cotton is not good for most cold, wet climates, it is useful in the desert. Light colored clothing reflects sunlight and lessens skin temperature. Ripstop cotton (cotton material with nylon threads latticed within it) is best because it resists rips that are common in the desert. It is light enough to allow heat to escape, does not creagte a clammy feeling in low humidity, and protects against some ultraviolet radiation exposure and blowing sand. If ripstop cotton is not available, then any tight weave cotton is adequate. Long sleeves and long pants are a must to protect againstspines, thorns, splinters and insects. More importantly, they protect against solar radiation that causes sunburn and increases body temperature, and trap more cool air next to the skin. Sweat that is trapped may decrease water loss via evaporation. Trousers can be tucked into the tops of socks to protect from insects; sleeves should be not be rolled up to minimize the risks of sunburn and heat gain. Gaiters can be worn to protect lower legs and the inside of footwear from sand, rocks, and dust. In a survival situation, puttees (wraps that extend from the tops of the shoes to the knees, either over trousers or bare legs, can be made from strips of cloth, elastic bandages, or stockings to protect the lower legs. They can be incorporated into the socks and wrapped to above the knees in a fashion similar to that for gaiters.

Because of the wide temperature swings, a pile jacket or sweater is necessary at night. Layering of clothing, just as for cold climates, is the best means of preserving body warmth. In a survival situation, any insulating material, such as seat cushions, newspapers or dry grass, can be used to insulate whatever clothing is available. Even though wind is more of a problem than rain, a Gore-Tex jacket is also recommended, especially for “cold” deserts. A wide brim hat or kepi (a cap with a cloth extending from the back protecting the neck) is necessary to protect the head, face, neck, and ears. In a survival situation, a head covering can be made from whatever material is at hand. A cotton cravat, bandanna, or handkerchief can be used to keep the head and neck cool by soaking the material in water (if plenty of water is available; do not use precious drinking water) and then placing it on the head followed by a hat, or wrapping around the neck and shoulders under a shirt. Commercially produced neck wraps (Cooldanna, Climatech, Stacool) and vests that contain crystals that can be soaked in water and then become cool through a chemical reaction are also available, but probably do not add much in the way of total body cooling in extreme environments The cravat can also be used during dust storms to protect the nose and mouth. It can also be used as a towel and to absorb moisture from plants when obtaining water.

High (6 inches) top boots composed of leather or synthetic materials are necessary to prevent sand, rocks, burrs from entering the boots, support the ankles on rough terrain, insulate the feet from hot surfaces, and prevent the boots being pulled off in soft ground. Boots should be well broken-in prior to hiking. Military issue boots with metal spike protection can become extremely hot in desert conditions and should be avoided. Running shoes do not insulate the feet well and may become extremely hot.

Socks should not be cotton, because of the risk of blisters and lack of wicking and insulation. Polypropylene or a combination of polypropylene and wool is the best for socks because of less friction and thicker material. Foot care is extremely important, especially in a survival situation when walking is the only means of transportation. Feet should be inspected for blisters, foreign bodies, and abrasions on a regular basis while hiking. Socks should be changed frequently, at least twice a day, to allow them to dry out and to remove accumulated dust and sand. Leather gloves are very desirable to protect hands from hot objects, plant spines, thorns and splinters, insects, and blisters.

Abrasions and lacerations to the hands can quickly become infected in conditions where hand washing is difficult. Eye protection becomes very important in the desert, especially when traveling. Solar radiation, both direct and reflected, can cause keratitis similar to snow blindness. More commonly, blowing sand, dust and insects may cause corneal abrasions and conjunctivitis. Contact lenses are difficult to manage in the dry, dusty environment. Tinted goggles are best, just as with mountaineering, but glacier glasses or standard sunglasses can be used. Duct tape, adhesive bandages or other material can be used to fashion side shields for regular glasses to prevent sand and dust from entering through the sides. Insect head nets can be lifesaving, especially in African, Arabian and Australian deserts, where insects and insect borne diseases are a particular problem.

Tags: , , , , ,
  • 1
Was this article helpful? Yes No
Advertisement

About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.

Advertisement