EVALUATION OF HOT ENVIRONMENT IN INDOOR ENVIRONMENTS TO PROTECT AGAINST HEAT DISORDERS

In order to protect heat disorder due to hot environment, the authors have developed a model forpredicting body temperatures, which has the following three characteristics: 1) regulatory thermalsweating is expressed as a linear function of the mean skin temperature under constant metabolic rate,2) sweat efficiency is expressed as a function of skin wettedness, and 3) the effect of wetted clothing,defined as clothing wettedness, caused by dripping sweat on physiological responses is considered.We proposed a prediction formula of heart rate in hot environment based on our model. This formulawas defined as functions of VO2max, metabolic rate, mean skin temperature and cardiorespiratorycapacity level, and was able to predict heart rate considering individual cardiorespiratory capacity. Acoefficient kadp of individual variability on regulatory thermal sweating was identified, which equals 1 foran average person. The analysis of sweating characteristics using human experimental data indicatedthat the variation of kadp appeared not only between individual subjects but between the same subjects.We described equal mean skin and core temperatures and heart rate lines calculated from the modelconsidering the individual variability under typical humid hot environmental and human conditions onpsychrometric charts. These charts made it possible to evaluate a risk of disorder caused by heat.