Therefore, work in the heat requires constant fluid replenishment. Since net water absorption in the gut is about 20 cc per minute or 1200 cc per hour, compensation for high sweat rates requires rest periods with reduced sweat rates and time for hydration. The degree of acclimatization is dependent on the degree of thermal stress to which the individual has been exposed. Regular vigorous exercise, even in temperate climates, produces sufficient elevation of core temperature to induce a small degree of heat acclimatization. However, any exposure to environment with significant additional heat stress will require an additional period of acclimatization.
Acclimatization develops at a rate that depends on the degree of heat stress imposed.
Achieving the maximum rate seems to require about 2 hours of continuous exercise exposure per day. The University of Iowa. All rights reserved.