High levels of exertion and physiological strain are the leading cause of fireground injuries. The Physiological Strain Index (PSI) provides a rating of strain based on body core temperature and heart rate; however, it may underestimate the strain of workers in protective clothing as skin temperature may be elevated. This study aimed to examine the relationship between the PSI and an Adaptive Physiological Strain Index (aPSI) that incorporates skin temperature, among firefighters wearing protective clothing. Nine male firefighters of the Australian Defence Force volunteered to participate. Participants conducted scenario-based activities while wearing turnout gear and breathing apparatus. Working in teams of four, participants would respond to a situation around and within a small building with several rooms that could be filled with smoke, however, no live fire was present. Heart rate, gastrointestinal temperature, and skin temperature were monitored throughout work and rehabilitation. Physiological strain was estimated via the PSI and aPSI. Absolute peak PSI and aPSI ratings were significantly different during work (PSI: 7.3 ± 1.6; aPSI 8.2 ± 2.0; p < 0.001). The aPSI produced higher ratings of physiological strain, >0.5 above PSI, progressively from a moderate level of strain (>6). The aPSI may provide a more accurate indication of a level of “maximal strain” for encapsulated workers than the original PSI, coincident with the occupational limits for body core temperature of 38.0 °C for general occupational groups, or 38.5 °C for selected and acclimatised personnel.

高水平的劳累和生理劳累是导致火灾的原因。生理应变指数（PSI）提供了基于身体核心温度和心率的应变等级；但是，由于皮肤温度升高，可能低估了工人穿着防护服的压力。这项研究旨在检查穿着防护服的消防员中PSI与纳入皮肤温度的适应性生理应变指数（aPSI）之间的关系。澳大利亚国防军的9名男消防员自愿参加。参加者在穿戴防暴装备和呼吸器的同时进行了基于情景的活动。参加者以四人一组的方式应对一栋小建筑物周围和内部的情况，该小建筑物内有几间可能充满烟雾的房间，但是，没有生火。在整个工作和康复过程中都要监测心率，胃肠温度和皮肤温度。通过PSI和aPSI估计生理菌株。在工作期间，PSI和aPSI的绝对峰值差异显着（PSI：7.3±1.6； aPSI 8.2±2.0；p  <0.001）。从中等水平的菌株（> 6）开始，aPSI产生更高的生理菌株等级，比PSI高> 0.5。与原始的PSI相比，aPSI可以为封装的工人提供更准确的“最大应变”水平指示，与一般职业人群的身体核心温度职业极限38.0°C或选定的和适应的38.5°C人员。