Effect of local ventilation temperature and speed under garments on the thermal response of humans at different metabolic rates.

Ventilation under garments is one of the effective solutions to alleviate heat stress in the human body, but ventilation preferences and cooling effects in different body segments at different metabolic rates are not thoroughly studied. Eighteen participants performed three metabolic intensities of cycling exercise at 30 °C, RH 35%, where five body segments underwent adjustable ventilation. The ventilation preferences, psychological and physiological responses, and energy consumption were analyzed. The preferred ventilation temperature was approximately 24.5 ± 1.9 °C and the preferred ventilation speed was 1.56 ± 0.29-1.68 ± 0.27 m s. At low and moderate metabolic intensities, the five body segments preferred similar ventilation temperatures. At high metabolic intensity, the back preferred lower ventilation temperatures and higher ventilation speeds than the lower limbs. Additionally, the lower back and chest are considered optimal ventilation body segments to achieve higher overall thermal comfort. This study contributes to the optimization of personal ventilated cooling garments for different metabolism scenarios.