Prediction computer program for whole body temperatures and its application under various working level and thermal environmental condition combinations

We introduced a computer program developed for the numerical analysis of thermal conditions of all segments and blood circulatory systems in the human body to precisely evaluate human thermal physiological responses. In this program, a cylindrical model consisting of internal multi-layers is adapted for the segment of the human body. For the multi-layered concentric cylindrical model we adopted a new numerical solution method. By using this computer program the internal tissue temperatures, heat fluxes and blood temperatures of all segments in the human body could be calculated simultaneously. This program also included a subroutine for calculation of thermoregulatory response. This paper describes the improvements made to this computer program for simulating individual physical differences and its application to various working levels. The main points for improvement were the assigning procedures of physical characteristics of individuals and local muscle heat production. The improved computer program was used to simulate the whole body temperatures of the subjects during exercise described in Gagge, Stolwijk and Saltin (1969) were simulated. The calculated results were agreed with the measured results under the combination of the three kinds of exercise and the three types of environmental condition.