Impaired working efficiency is a well-known consequence of heat strain. This is particularly important in military services. Core temperature is considered a relevant indicator of thermal strain. Military training guidelines for continuous physical work times are based on achieving core
temperature of 40ºC in acclimatized individuals with appropriate fluid replacement 11. Well-trained athletes and soldiers
may tolerate hyperthermia without adverse side effects due
to training-induced heat acclimatization effects on cellular
protective mechanisms