Effect Of Indoor High Temperature Environments On Physiological Circadian Rhythm Of Young People

There is a large proportion of indoor non-air-conditioned environments in actual life,and the physical health and work efficiency of indoor crowds are more vulnerable to indoor high temperature in summer.Firstly,the study of circadian rhythm is of great significance to the health protection,low-performance awareness pridiction and life quality improvement.Secondly,the frequent high temperature weather may cause cumulative effects on the human physical health.Lastly,the quantitative assessment of the physiological state of human body in the high temperature environments can greatly reduce the threat to their physical health caused by high temperature environments.Therefore,the diurnal variation of human physiological parameters and work efficiency in high temperature environments was studied,the cumulative effect of continuous high temperature weather on human physiological strain was quantified,and a comprehensive evaluation model of human physiological state based on multiple physiological indicators was established in this paper.This study can provide guidance for the physiological state evaluation and safety protection of the relevant people in indoor high temperature environments.Field experiments were conducted to study the physiological response of human body in an actual non-air conditioned environment in this paper.Ten college students were selected as subjects,and the experiment s were consisted of two parts.Experiment one:The maximum hourly outdoor temperature in summer was selected as 28?,32?,36?and 38?,the physiological parameters and ergonomic indexes of the subjects in the non-air-conditioned house were measured for 24 hours continuously.Meanwhile,the indoor and outdoor environmental parameters were recorded.The physiological parameters included systolic blood pressure,diastolic blood pressure,heart rate,rectal temperature,eardrum temperature,forehead temperature,mean skin temperature and sweat rate;and the ergonomic indexes included the response time?RT?of numeral inspection task and stroop color word test,grip strength,and subjective work willingness.Experiment two:Continuous high temperature weather with the maximum outdoor temperature?35?for three consecutive days was selected as the study condition,meanwhile the systolic blood pressure,diastolic blood pressure,heart rate,rectal temperature,mean skin temperature and the RT of numeral inspection task and stroop color word test were measured for 12 h continuously.For experiment one,the variation laws of circadian rhythm of human physiological parameters and ergonomic indexes in high temperature environments were analyzed.Firstly,the relations of rhythm eigenvalue with temperature were fitted.Secondly,the correlation analysis was carried out between the the ergonomic indexes and the physiological parameters.The results indicates that the forehead and eardrum temperature show a significant negative correlation with the RT in the high temperature environment s.Thus forehead temperature can be used as a predictor for assessing the individual ergonomics.For experiment two,the changes of the physiological parameters at the same time point in these three days were analyzed by paired T-test.Then an evaluation method for quantifying cumulative effects was proposed.The daily maximum temperatures of these three days were corrected based on the temperature correction model,thus the cumulative effect were quantified.The results indicate that the continuous high temperature has an unfavorable cumulative effect on systolic blood pressure,diastolic blood pressure,rectal temperature and mean skin temperature.Among the above physiological parameters,the cumulative effect coefficient of the first day before a certain high temperature day?₁K?>the cumulative effect coefficient of the second day before the high temperature day?₁K?,and the rank ofK₁ of the physiological parameters is:the mean skin temperature>systolic blood pressure>diastolic blood pressure>rectal temperature.Based on the fuzzy comprehensive evaluation method,a comprehensive evaluation model of human physiological state was constructed.The membership functions of the evaluation indexes relative to the evaluation grades were determined,and the weights of the evaluation indexes were determined by the sensitivitity analysis method.Then the physiological state of the human body was quantified.The results indicate that the weights of the physiological indexes change with the ambient temperature.And the sensitive weights are ranked as:skin temperature>rectal temperature>systolic blood pressure,heart rate and sweat rate.The physiological score of the human body decreases with the increasement of the ambient temperature.The model can realized the quantitative analysis of the physiological state of the human body,and the comparison results demonstrate the effectiveness and reliability of the proposed approach in the case analysis.Furthermore,this study can provide guidance for the physiological state evaluation and safety protection of the relevant people in indoor high temperature environments.