THERMODYNAMIC EVALUATION OF PSYCHOPHYSIOLOGICAL STRESS RESPONSES

Abstract

The present study provides a novel methodology to characterize and measure psychophysiological stress responses. Using thermodynamic Maxwell relations, it combines five physiological variables including diastolic blood pressure (DBP), heart rate (HR), facial electromyogram (EMG), skin conductance level (SCL) and finger skin temperature (ST) to provide a quantitative measure of stress response in terms of entropy generation. The study involving eighty-eight medical residents (37 females and 51 males) provided the needed data for thermodynamic evaluation. A biofeedback system recorded five physiological variables under three states (relaxation, stressor, and recovery) in a test profile. The entropy generation (Sgen) during the relaxation, stressor task and recovery states is calculated. There were two entropy generation metrics, one for Thermal-Fluid System (DBP, HR, and ST) and the other for Thermo-Electric System (EMG, SCL, and ST). A single-factor ANOVA test demonstrates statistically significant difference in stress response to relaxation, stressor and recovery states with-in male and female subjects. Furthermore, the t-tests did not show any statistically significant difference between male and female stress responses to relaxation, stressor, and recovery states. The study presents a holistic approach to quantify human stress response that could be valuable for ergological evaluation of workplace stress and productivity.