The effect of biological sex on cool seeking behavior during passive heat stress in young adults.

PURPOSE

This study tested the hypothesis that females engage in cool seeking behavior to a greater extent during passive heating compared to males.

METHODS

27 healthy participants (14 males) underwent two trials of 50 min lower leg passive heating with (Fan trial) and without the fan (No fan trial) in a 27 °C, 50% relative humidity environment. In the Fan trials, participants were allowed to use the fan by pressing the button to keep themselves comfortable while they were not allowed in the No fan trial.

RESULTS

Cool seeking behavior was initiated at the same change (∆) in rectal temperature (0.2 (0.2) °C vs 0.2 (0.1) °C, p = 0.281) and ∆ mean skin temperature (2.1 (0.6) °C vs 2.3 (0.6) °C, p = 0.307), but cooling time was longer (13.5 (5.4) min vs 17.3 (3.9) min, p = 0.040) and cumulative number of times pressing the button is more often (7.3 (3.6) times vs 10.8 (4.6) times, p = 0.049) in females compared to males. Thermal sensation, thermal discomfort, and perceived skin wetness were not different between sexes during lower leg passive heating in all trials (all p > 0.145). Furthermore, whole body sweat loss and local sweat rate on the forearm were significantly higher in males compared to females (all p < 0.042) across Fan and No fan trials.

CONCLUSION

In conclusion, females engage in cool seeking behavior to a greater extent than males. Furthermore, thermal perceptions are not different between sexes during passive heating.