A new individualized thermoregulatory bio-heat model for evaluating the effects of personal characteristics on human body thermal response

Personal factors such as weight, height, gender, age, and basal metabolic rate (BMR) all have significant effects on body temperature distribution and thermal sensation. A large number of well-known human body thermoregulatory models are population-based however, and cannot evaluate the impact of individual characteristics on human thermal responses. Further, the standard thermal models of the human body, including Fanger's and Gagge's, are based on the energy balance approach. However, a person's thermal sensation is affected by the thermal response of cutaneous thermoreceptors relative to the environmental thermal conditions, and it is not necessarily related to the energy balance of the human body. Thus, these simplified standard models have some limitations under various individual conditions and are not in conformity with the physiology of individual thermoregulatory mechanisms. This study proposes a new Individualized Thermoregulatory Bio-heat (ITB) model on the basis of Pennes' equation and Gagge's 2-node model to determine heat transfer in living tissue layers. In developing this model, the effects of individual parameters such as age, gender, body mass index (BMI), and BMR on determining the temperature and its derivatives at cutaneous thermoreceptor locations were considered. Afterward, the present model was validated against the published empirical data, simulated standard model results, and analytical results under various environmental conditions and a good agreement was found.