Men and women adapt equally well to heat acclimation but through different physiological pathways

A controlled 10-day heat acclimation protocol was applied to 27 healthy young adults—16 women and 11 men—who walked at a fixed pace in hot, humid conditions while researchers tracked core temperature, heart rate, sweat output, and a cellular stress protein. Both sexes reached comparable improvements in heat tolerance by the end of the protocol, even though the biological routes they took to get there differed in meaningful ways.

What the study found

Both men and women showed statistically significant reductions in peak core temperature across the 10 days, with the magnitude of improvement roughly equivalent between the two groups. Heart rate also declined meaningfully in both sexes over the course of the protocol, though women maintained higher heart rates throughout compared with men.

Whole-body sweat rate increased in both groups, but the pattern differed: men sweated more heavily in the early days of the protocol, while women's sweat output rose more modestly and reached a lower absolute level by day 10. Despite this gap in sweating, the two groups ended up with similar core temperature outcomes, suggesting that women may rely more on other heat-dissipation mechanisms to compensate.

A cellular stress marker—heat shock protein 72, which is produced in response to thermal stress and is thought to play a role in cellular protection—rose to a similar degree in both men and women over the 10 days. The authors note this is the first reported evidence of comparable heat shock protein 72 responses across sexes during a standardized heat acclimation protocol.

Overall, the authors interpret these findings as evidence that the two sexes are equally capable of adapting to repeated heat exposure, but that the underlying physiological mechanisms driving that adaptation are not identical. They caution that the results apply specifically to the controlled exercise-in-heat model used and may not generalize to all forms of heat exposure.

Limits worth knowing

The sample was small (27 participants, 16 women and 11 men), which limits statistical power for detecting sex differences in secondary outcomes. All participants were young and healthy, so findings may not extend to older adults, those with cardiovascular conditions, or other populations. The protocol involved exercise in a controlled environmental chamber rather than passive heat exposure such as sauna bathing, which constrains direct applicability to non-exercise heat modalities. The study was conducted at a single site. Non-U.S. government funding was disclosed, though the specific source is not detailed in the available information. Longer-term retention of adaptations was not assessed.

About this entry. The Heartwood Review summarizes published, peer-reviewed research in its own words and links to the original source. It is not medical advice; consult a physician before beginning or changing any thermal or recovery practice. Findings summarized here describe the study cited, not any product sold by Teak & Marble Atelier. Corrections.