2026 年 28 巻 2 号 p. 01-11
Background: This study investigates the potential sex differences in autonomic and subjective thermal responses preceding the decision to behaviorally thermoregulate by local cooling during passive exposure to humid heat. Given the known differences in physiological and subjective responses to thermal stress among males and females, it is hypothesized that sex differences exist in the temporal recruitment of autonomic thermoeffectors and changes in subjective thermal responses preceding local cooling during humid heat exposure.
Methods: Ten young male and nine young female adults were recruited to participate in this study, where behavioral thermoregulation by local cooling was allowed at any point during the experimental trial while passively exposed to humid heat (33°C and 80% RH). The autonomic responses measured include core, mean body, and skin temperatures, as well as local sweat rate and skin blood flow, all obtained preceding behavioral thermoregulation. Additionally, subjective thermal responses upon initiating local cooling were also recorded.
Results: Contrary to our hypothesis, the results revealed no differences in temporal recruitment of autonomic thermoeffectors and changes in subjective thermal responses preceding behavioral thermoregulation. Thus, the autonomic thermoeffectors for both males and females follow an orderly recruitment pattern during humid heat exposure. However, it was observed that female participants perceived a lower level of skin wetness perception and thermal comfort than males at the time when they initiated behavioral thermoregulation by local cooling.
Conclusion: There are no differences in the temporal recruitment of autonomic thermoeffectors and changes in subjective thermal responses when deciding to initiate local cooling during humid heat exposure between males and females.
