Study On Physiological Responses Of Relaive Population In Hot And Humid Environments

Hot and humid environments, widespread in modern society, greatly threatenworkers’ health and safety. Physiological responses when working in hot and humidenvironments, and the relationships between physiological responses and theirinfluence factors are important subjects to ensure safety and avoid accidents.The experiment system for physiological responses working in hot and humidenvironments was established. Some male youths were selected as subjects. Theenvironment temperatures were set at32℃,36℃and40℃, the relative humiditywere set at40%,60%and90%, and the air velocities were set at without airmovement and with air movement. The whole experiment process was composed ofwork process and recovery process. Both in the work process and the recoveryprocess, the heart rate, rectal temperature, oral temperature, ear tympanic temperature,two-point threshold, the amount of sweat, respiration, oxyhemoglobin saturation, ECG,fatigue degree and thermal sensation were measured.The physiological responses both in the work process and the recovery processwere obtained. The physiological responses when working in hot and humidenvironments with air movement were compared with those when working in hot andhumid environment with air movement.Physiological recovery rate was defined to determine the physiological recoverytime of each physiological parameter, then the reference recovery times when workingin the hot and humid environments were determined. The results of the recovery timefor people working in hot and humid environments are: light work without airmovement,76min; moderate work without air movement,79min; heavy workwithout air movement,55min; light work with air movement,60min; moderate workwith air movement,59min; and heavy work with air movement,66min.The relationships among the physiological parameters during work in hot andhumid environments were obtained. According to these relationships, a simple methodfor calculating the energy metabolism rate was established.The significance analysis of the effects of the temperature, relative humidity,work intensity and work time on the physiological parameters was individually conducted. The results indicate that, the effects of the temperature, relative humidity,work intensity and work time on the physiological parameters were different.A factor decomposition model for the physiological parameters was established.The temperature induced effect, the relative humidity induced effect, the workinduced effect and the superimposed effect were defined to quantify the physiologicaleffects caused by the temperature, the relative humidity and the work intensity.The weights in the formula of the existing PSI and WBGT were corrected. And aphysiology based corrected PSI and a physiology based corrected WBGT wereproposed.Safe work time was calculated based on the safe physiological limit. Coxregression method was adopted to study the influence factors of the safe work time.The recommend values for the safe work time in hot and humid environments wereproposed. Finally, the safe work time predict model, the physiological responsesclassification system and the time response model of the physiological responses wereestablished. The results will provide data and methodology for the establishment andrevision of some relative standard and criterion. They will also provide reliableprotection system for the workers’ safety in hot and humid environments.