# Human simulation model for predicting body temperature, blood pressure, and blood flow rate under various thermal exposures — Part 1: development of physical model for average Japanese male in their 20s

## TL;DR

This paper develops a human body simulation model to predict body temperature, blood pressure, and blood flow rate in an average Japanese male in their 20s under thermal conditions.

## Contribution

A new physical model combining thermal and cardiovascular simulations for predicting physiological responses in a specific demographic.

## Key findings

- The physical model accurately reproduces experimental body temperature, blood flow rate, and blood pressure values under thermally neutral and supine conditions.
- The model integrates a thermal network and cardiovascular system to simulate heat and blood transfer phenomena.

## Abstract

In the mechanism of thermal health problems, not only body temperature but also blood pressure and blood flow rate are key factors. Human body simulation is a useful tool for predicting these physiological quantities under various conditions. Therefore, we aimed to develop a new human-body simulation model to predict body temperature, blood pressure, and blood flow rate. Our model consists of a “physical model” that simulates the phenomena of heat and blood transfer based on the physical properties of the human body, and an “autonomic regulation model” that simulates the phenomena in which the physical properties of the human body are regulated by the activity of the autonomic nervous system. The physical model consists of a “thermal network (TNW) model” that simulates heat flow and body temperature, and a “cardiovascular (CV) model” that simulates blood flow and blood pressure. In this study, we focused only on developing the physical model. In addition, based on experimental data from a recent study, parameter settings were derived to simulate an average Japanese male in their 20s. By applying the derived parameter settings to the physical model developed in this study, we confirmed that the calculated body temperature, blood flow rate, and blood pressure under a thermally neutral and supine condition reproduced the experimental values well.

The online version contains supplementary material available at 10.1007/s00484-025-03072-6.