Physical symptoms provoked by normobaric hot and humid disabled pressurized rescue module scenarios

We tested the hypothesis that thermal discomfort will be greater, mood will be worse, and physical symptoms of heat illness will be exacerbated with elevations in dry bulb temperature during exposure to >95% relative humidity disabled pressurized rescue module simulation. On three occasions, 15 healthy males (23 ± 3 years) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C or 35.0 ± 0.1°C, and 95 ± 2% relative humidity normobaric environments for eight hours. Thermal discomfort (visual analog scale), mood (profile of mood states), and physical symptoms of heat illness, ear-nose-throat, and muscle discomfort (environmental symptoms questionnaire) were assessed before and following each hour of exposure. Thermal discomfort was greater throughout the exposure in 35°C versus both 32°C and 33°C (p ≥ 0.03) and did not differ between the latter conditions (p ≥ 0.07). Mood worsened over time in all trials (p ≺ 0.01) and was worse in 35°C compared to 32°C and 33°C after five hours of exposure (p ≤ 0.05). Heat illness symptoms increased over time in all trials and was greater in 35°C versus 32°C and 33°C throughout the exposure (p ≤ 0.04). Ear-nose-throat and muscle discomfort symptoms increased over time in all trials (p < 0.01) and were higher in 35°C versus 32°C and 33°C after the sixth hour of exposure (p ≤ 0.02). In support of our hypothesis, mood was worse, physical symptoms of heat illness, and ear-nose-throat and muscle discomfort symptoms were exacerbated, and thermal discomfort was greater with elevations in dry bulb temperature during an eight-hour exposure to a >95% relative humidity disabled PRM simulation.