Effects of heat acclimation on individual safety performance in hyperthermal indoor environments

Hyperthermal indoor environments are ubiquitous in industrial processes. Tremendous heat stress exacerbates workers' fatigue, thereby threatening their safety. Heat acclimation (HA) has many benefits in preventing hyperthermia, but its mechanism and effect on the safety performance remain uncertain. This study designed a dodge ability testing system (DATS) to evaluate individual safety performance by detecting human errors at work and conducted a series of human subject experiments. The participants were equally divided into two groups for the conditions of WBGT 1/4 28. C and WGBT 1/4 30. C to be trained in a heat chamber to become heat-acclimatized. Their core temperature (Tc), skin temperature (Ts), heart rate (HR), and sweat rate (SR) were measured in real time, and their errors was measured using the DATS at the end of each training session. The peak values of these parameters and the rates of the human errors were recorded for paired sample t-tests to reveal the differences before and after HA training. Furthermore, consistency checks were employed to identify the magnitude and time course of HA. The results show that HA could effectively lower the peaks of the physiological parameters and that the higher heat stress may have no influence on the magnitude but shorten the time course. And more importantly, HA could attenuate detrimental effects of heat stress and fatigue on the ability to act but have no influence on the ability to cognize danger. In conclusion, HA could effectively improve individual safety performance in hyperthermal indoor environments by reducing their human errors.