Evaluation Model Of Cognitive Impairment In High Temperature Based On Heart Rate

Heat waves caused by global warming have become one of the major natural disasters in summer.The safety and life health of workers working at high-temperature environment are facing severe challenges.We should pay more attention to the accidents caused by hightemperature weather,which would lead to severe threaten to both human life and economic development.In this paper,the effects of high temperature on cognitive performance of low activity(sedentary position)were studied.Five temperatures: 26°C,30°C,33°C,37°C and 39°C,and two relative humidity: 50% and 70% were set at the experiments.Three periods of experiments were conducted to obtain physiological parameters,subjective feeling and cognitive test scores of subjects at high temperature carrying out low-intensity activities.As the result shown,the thermoregulatory activity of subjects increasing,the subjects’ discomfort increased significantly,complete cognitive test speed significantly increased,accurate rate dropped significantly with the increasement of temperature and relative humidity.Combining with the physical parameters and subjective sensation vote,the influence on cognitive test scores was discussed.The subjective and physiological parameters was conducted to quantify the relative contribution of test scores,then the Thermal Stress Comprehensive Index was brought up.The relation between thermal stress and the cognitive performance was built up as TSCI-CP model.The results showed that with the increase of TSCI,the completing speed of cognitive test presented a U-shaped change trend,while the accuracy presented an inverted Ushaped change.In addition,this paper also explores the influence regularity and relationship between heart rate and cognitive performance under high temperature.The results show that the cognitive test scores changed significantly with the increasement of heart rate.The TSCI-CP model is used as a reference to build up the prediction model(HR-CP Model)of cognitive performance impairment based on heart rate at high temperature.The fit goodness of the quantitative relationship model(HR-CP Model)between heart rate and relative accuracy was close to or greater than 0.8.The inverted U-shaped curve equation reasonably reflected the changing trend of the relative accuracy,which was consistent with the description of accuracy by TSCI-CP model.