188 Training for Specific Environments
" Dehydration.
" Salt depletion.
" Illness/Infections.
" Cessation of physical activity.
There is some disagreement as to how long it takes to lose acclimation to heat, but
generally speaking after 2 weeks of working in a hot environment, it will take 3 to 4 weeks
before most of the adaptations are lost.
Heat Injuries
There are many categories and subcategories of heat injuries. However, there are
three classes of heat-induced injuries that will be considered here:
" Heat cramps are painful contractions of muscles (usually in the extremi-
ties) following vigorous exercise. They occur most commonly in unacclima-
tized personnel. No specific cause is known (possibly depletion of
electrolytes), but such cramps usually resolve when acclimation is complete.
" Heat exhaustion is a potentially serious injury resulting primarily from
dehydration and electrolyte depletion. The affected individual may feel light-
headed, dizzy, nauseous, fatigued, or develop a headache. If heat exhaustion
is suspected, the injured individual should be placed in a cool location if pos-
sible and given replacement fluids by mouth or intravenously.
" Heat stroke is a life threatening injury in which the affected individual
loses the ability to regulate temperature and is overcome by soaring body
core temperatures (greater than 104° F). Such high temperatures can irrevers-
ibly injure vital organs and result in death if not rapidly treated. Many factors
may contribute to heat stoke -- even well hydrated personnel may become
victims if they ignore the warning signs and symptoms (see the following
Table).
Table 11-1. Warning Signs of Heat Stroke
Signs to Be Aware of
Light-headedness Headache