JP 3-50 National Search and Rescue Manual Vol I - US Navy

ody size, build, fatness, physical fitness, and state of
health. The zone would include approximately 95 percent of
the variation expected for adult and teenage humans under the
conditions specified. Factors that make a person a slower
cooler are: high body weight, heavy clothing, use of survival
clothing, or the use of a huddling or other protective
behavior. Factors that make a person a faster cooler are: low
body weight, children, light clothing, or exercising such as
persons without PFDs having to swim. The zone would be
shifted downward by physical activity (e.g. swimming) and
upward slightly for heavy clothing and/or protective behaviors
(e.g. huddling with other survivors or adopting a fetal
position in the water). Specialized insulated protective
clothing (e.g. survival suits, wet suits, etc.) are capable of
increasing survival time from 2 to 10 times (or more) the
basic duration shown here. In the zone where death from
hypothermia is highly improbable cold water greatly
facilitates death from drowning, often in the first 10 to 15
minutes, particularly for those not wearing flotation devices.
{2} However, cardiopulmonary resuscitation (CPR) still should
be performed, particularly if immersion has not exceeded 60
minutes.
b. Wind is an additional factor for exposed survivors,
as body heat loss accelerates with increasing wind velocity.
Figure 4-2, Equivalent Temperature curves, shows the effects
of various wind speed and air temperature combinations and
indicates the equivalent temperature on dry skin in still air.
These curves emphasize the necessity for shelter of survivors
exposed to severe cold. In temperatures below 0 degrees F (-18
degrees C) survivors become easily fatigued.
2. Heat stress and dehydration are dangers in hot climates,
particularly desert areas. The most severe form of heat
stress is heat stroke, when body temperature rises because of
the collapse of the temperature control mechanism. If the
body temperature rises above 107 degrees F (42 degrees C) for
sustained periods, death usually occurs. Dehydration is a
critical factor both in hot climates and in sea survival; a
person without water will die in a few days. A combination of
high temperatures and lack of water will quickly aggravate
heat stress and dehydration. The life expectancy of survivors
in a desert environment is shown in Figure 4-3. In high
humidity areas, the water needs of the body are about one-half
those in deserts at equal temperatures.
3. The presence of certain animal life may increase hazards and
reduce expected survival time. The SMC should be aware of
what animals may be in the search area and where to acquire
specialized medical help quickly.