Effect Of Individual Differences On Physiological Responses Under Hot-Dry And Hot-Humid Environment

With the rapid development of technology, the Hot-Dryand Hot-Humid environmenthas universally existed in numerous industries.The human's physical and mental healthmay be seriouslydamaged when people working in this environment, which has been proved by many studies. In this paper, an exploratory research on the effect of environment and anthropometric characteristics on human physical responsesis conducted by carrying on large scale heat duration experiment.A high thermal and humid environment chamber was used to simulate a comfortable environment, a Hot-Dry environment and a Hot-Humid environment, respectively. Meanwhile, 60 healthy volunteered university students with different somatotype and habitus characters were selected to exercise at low and high intensity on the treadmill.The respiration, heart rate, skin temperature, two-point temperature, rectal temperature and sweat loss of subjects was measured during experiment process, as well as the heat tolerance time of subjects.The subjects were categorized into four types according to their somatotype and habitus characters: A type(thin and strong), B type(thin and weak), C type(fat and strong), D type(fat and weak). Several results can be obtained by analyzing experimental data: firstly, under the same black ball temperaturecondition, there is a significant difference between different subjects' physiological characteristics variation trends when subjects exercise in the Hot-Dry and Hot-Humid environment respectively, and the heat strain of the subjects exercising in Hot-Dry environment is apparently higher than the subjects in Hot-Humid environment; secondly, although physiological characteristicdifferences existing in the subjects of four types, all subjects' heat strain show a high level andthe differences subside when the experiment intensityincreasing; thirdly,significant differencesof anthropometric characteristics variation trends are found between male and female subjects and is higher than the male subjects; fourthly, the heat tolerance time ofthe subjects in Hot-Humid environment is much longer than the subjects in Hot-Dry environment, at the same time, the intensity also has more or less impact on the heat tolerance time; lastly, there are individualand gender differences in the heat tolerance time.Based on the BCI(Body Characteristic Index), the RBCI was developed. The RBCI, in which the rectal temperatureis closer to core temperature and selected to replace the oral temperature in the BCI, can evaluate the relative level of human heat stress responses during heat exposure in a much bigger group of people and predict the variance of physiological characteristics with more accuracy.