(2) Process of acclimatization. Acclimatization to heat begins with the first
exposure and is usually developed to about 45-52 percent by the end of the first week.
Individuals who are unusually susceptible to heat will require additional time for
acclimatization. Full acclimatization (the ability to perform a maximum amount of
strenuous work in the heat) is attained most quickly by graded, progressively increasing
work in the heat. Full heat acclimatization can be achieved by as little as two 50-minute
periods of work in the heat of each day. The work task should require cardiovascular
endurance work; e.g., running in place, rather than muscle work; e.g., pushups.
(a) Resting for three or four days in the heat, with activity limited to that
required for existence, results in only partial acclimatization. Physical work in the heat
must be accomplished for development of full acclimatization to an acceptable work
level in a given hot environment.
(b) A day or two of intervening cool weather will not interfere
significantly with acclimatization to a hot climate.
(3) Work schedule during acclimatization period. If individuals must work
during the acclimatization period, advantage should be taken of the cooler hours in
accomplishing the work. A schedule should be established which provides for
increasingly longer work periods alternating with rest periods.
(a) The plan which follows is suggested for troops other than basic
trainees. It is not advisable for basic trainees to work in the heat during the basic
training period when risk of heat injury is high. The schedule shown in table 4-1 should
be modified to be consistent with local conditions.
Table 4-1. Schedules of work during acclimatizing period.
(b) Divide the work period so that an individual works and rests in
alternating periods. When it is necessary for the accomplishment of a given task, two
details can be arranged to work in sequence.