Physiological Responses of Physically Fit Men and Women to Acclimation to Humid Heat,
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
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Four men and four women with comparable maximal aerobic capacities and equal surface areas and surface area to mass ratios underwent a three hour heat stress test before and after a 10 day acclimation to humid heat. Women were tested during both pre- and post-ovulation pre-OV, post-OV. Prior to acclimation, pre-OV women exhibited the longest tolerance times and lowest rectal temperature TRE and heart rates HR throughout testing. Men secreted considerably more sweat per unit area than did women in either phase of the cycle, yet they demonstrated shorter tolerance times and higher body temperatures and HR. During post-OV, women reacted similarly to men, although their sweat rates and HRs were significantly lower. Following acclimation, the TRE and HR of the men and women were similar while the discrepancy between the sweat rates was magnified. It was concluded that aerobic capacity is an important factor to be considered when men and women are compared in the heat. When fitness levels are similar, except for sweating, the previously reported sex-related differences in response to heat seem to disappear.
- Stress Physiology