Sex differences in acclimation to a hot-dry environment†;

Abstract

Sex-related differences in acclimation to a hot-dry environment were evaluated in ten males and nine females. The subjects were exposed during early spring to a hot-dry climate: 49DC, 20% rh for 6 consecutive days. Exposures lasted 120 min: l0min rest, 50min walk (l.34ms⁻¹1), l0min rest, 50min walk. Heart rate, rectal temperature (T_re), mean skin temperature (T_k), and heat storage dropped significantly for both sexes (p <0.05) from the 1st to the 6th day, with no significant changes (p > 0.05) between the last 2 days. In spite of similar metabolic rates, similar sweat rate and lower heat gain by radiation and convection for the females, their T_re and T_k remained significantly higher (p <0.05) than those for the males at the end of acclimation. It was suggested that the thermoregulatory set-point is higher for unacclimated women than for men, and that this difference does not disappear with acclimation.

Notes

†The views, opinions, and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy, or decision, unless so designated by other official documentation.