Active Heat Acclimation Training Offered Better Results in Thermal Rooms in Basic-Training Troops: A Prospective Controlled Study

Heat acclimation is a critical strategy for preventing heatstroke in military personnel, but traditional heat acclimatization relies on natural environments, unfeasible for military training. This study aimed to establish mobile cabin-type thermal rooms in basic-training troops and evaluate the effects of active and passive heat acclimation training in new soldiers. Mobile cabin-type thermal rooms were constructed in basic-training troops. New soldiers underwent heat tolerance tests, and those identified with poor heat tolerance were randomized into active or passive training groups. Following heat acclimation training, participants were re-evaluated, and physiological responses were compared between groups. A total of 1326 male new soldiers participated in the heat tolerance test; 134 (10.1%) were identified with poor heat tolerance. Among them, 70 were assigned to the active training group and 64 to the passive group. All participants completed training and subsequently passed the heat tolerance test. Both groups showed significant improvements in core physiological and stress indices ( P < .05), with no statistical differences between groups ( P > .05). However, the rise in core temperature and heart rate occurred faster in the passive group, while a higher proportion of soldiers reported comfort in the active group ( P < .05). Mobile cabin-type thermal rooms provide a reliable, rapid method for screening and training heat tolerance in basic-training troops. Both active and passive heat acclimation improved heat tolerance, but active training offered better subjective comfort. This approach enables safe and effective preparation for military personnel in hot environments.