LESSON 4
HEAT INJURIES
Section I. CHARACTERISTICS/GENERAL FINDINGS OF HEAT INJURIES
4-1.
INTRODUCTION
The environmental conditions to which troops must adapt can vary greatly.
Troops participating in maneuvers near the Soviet border may encounter the extremes
of the Arctic cold while troops participating in maneuvers in the Middle East must adapt
to the extremes of equatorial heat. An inability to adapt to environmental conditions can
very often lead to heat and cold injuries. As a Medical NCO, you must know the
preventive measures as well as the treatment for heat and cold injuries that result when
troops do not adapt to their environment. In this lesson, information regarding heat
injuries will be given.
4-2.
GENERAL
People engaged in outdoor activities are susceptible to illnesses from exposure
to heat, especially in the warmer areas of the world as well as all parts of the world in
the warmer periods of the year. Illnesses from exposure to heat are also seen in
industries in which the environment is very hot. Often, overexposure to heat will occur
when a person has just arrived in a very hot climate or in the early part of the year. In
either case, the human body has not had the chance to adjust to the higher
temperatures.
4-3.
CAUSE AND IMPORTANCE
a. When a person gets hot, his body perspires. The perspiration evaporates
causing the body to cool. In addition to water, perspiration contains salt. Salt helps to
regulate nerve impulses and muscle reactions. If the water and salt lost through
perspiration are not replaced, heat injury can result. There may be peripheral
vasodilation (external surface dilation of a vessel, especially dilation of arterioles leading
to increased blood flow to a part); increased cardiac output (increased systolic pressure
of 120 mm or higher, as high as 180 mm); and sweating. Sweating leads to dehydration
resulting in circulatory instability. If the person remains erect and immobile, syncope
(fainting) may result. (Note: Muscular activity usually prevents fainting.)
b. The three principle types of heat injury are heat cramps, heat exhaustion, and
heatstroke. Heatstroke is also called sunstroke, heat pyrexia, and hyperthermia. Heat
cramps and heat exhaustion will prevent a person from performing his mission
effectively and can develop into heatstroke. Heatstroke is fatal if effective measures are
not taken immediately.
MD0587
4-2