Development of JOS-2 human thermoregulation model with detailed vascular system

A human thermoregulation model called JOS-2 was developed based on the Stolwijk model and our previously developed (in 2002) JOS model. In this model, the whole body was idealized as 17 spherical or cylindrical body segments (Head, Neck, Chest, Pelvis, right and left Shoulders, right and left Arms, right and left Hands, right and left Thighs, right and left Legs, and right and left Feet). The Head segment consists of four layers—core, first layer, second layer, and skin—and the other segments consist of two layers—core and skin). All body segments have artery and vein blood pools. In addition, the limb segments have a detailed vascular system consisting of superficial veins and arteriovenous anastomoses (AVA). Thermoregulatory mechanisms such as vasoconstriction, vasodilation, perspiration, and shivering are considered. The physical parameters of this model, such as height, weight, sex, age, body fat percentage, basal metabolic rate, and cardiac index, can be changed. This paper describes the equations and coefficients as well as the model validation for stable, nonuniform, transient conditions.