Soldiers required to deploy with little notice to hot environments will arrive unacclimatized regardless of their physical condition. Acclimatization will require 7-10 days. During the acclimatization period, troops that must work vigorously should be provided copious quantities of water and carefully supervised work-rest cycles tailored to their physical capacity by direct medical oversight. Acclimatization should eventually eliminate the need for salt supplementation. Command directed drinking is effective in moderating dehydration and must be enforced.
Dehydration profoundly reduces thermoregulatory and physical capacity.
Fever whether due to immunization or illness, reduces thermoregulatory capacity and increases the risk of heat illness. Soldiers recovering from fever will have increased susceptibility to heat illness even after all clinical evidence of illness has disappeared. Until clearly able to manage normal work rates in the heat they will require increased command supervision and moderated work schedules. The requirements of military operations frequently produce lack of sleep, missed meals and limited availability of water. All these factors reduce thermoregulatory capacity and increase the risk of heat illness.