Fuzzy comprehensive evaluation of human physiological state in indoor high temperature environments

Abstract

Quantification of physiological state is a key issue for human physiological safety in high temperature environments. In this study, the fuzzy comprehensive evaluation method is introduced into the physiological state evaluation in indoor high temperature environments. Five physiological parameters (skin temperature, rectal temperature, heart rate, systolic pressure and sweat rate) are selected as the evaluation indexes, then the membership functions of the evaluation indexes are proposed to determine their membership degrees related to the evaluation grades. Based on the sensitivity analysis method, the sensitivity weights of above physiological parameters are determined. Then a comprehensive evaluation model for quantifying the physiological state is established. And physiological state score (PSS) is proposed to rank the safety level of the physiological state. Finally, the evaluation model is applied and verified in a case study. The results indicate that the weights of each physiological index change with the ambient temperature. The weights of the skin temperature and the rectal temperature account for a relatively large proportion, ranging from 81.8% to 88.5%. The safety levels ranked by the physiological state score are similar to the heat strain levels ranked by the physiological strain index values. The comparison results demonstrate the effectiveness and reliability of the proposed approach. The application of fuzzy comprehensive evaluation and sensitivity analysis provides a new scientific method for quantifying the human physiological state. This study can provide guidance for the physiological state evaluation and safety protection of relevant people in indoor high temperature environments.