摘要：Mathematical modeling of thermal responses allows testing of wide performance limitations in individuals exposed to environmental extremes. One important application is in the determination of hazard materials (HAZMAT) workers’ endurance times to execute a task. The simulation approach is especially important when operational settings with such individuals are restricted to finite thermal limits necessary to protect the individual. In essence, the ideal mathematical model of thermal strain (both heat and cold stress) should incorporate all essential variables active in thermoregulation. Although almost an insolvable task, a great many worthwhile models do a reliable job describing the heat balance equation. Models are quite useful in a first approach prediction of physiological effector response (sweating rate, skin blood flow, etc.), particularly when a given metabolic activity stays constant over the time of the given exposure. Early forerunners of rational thermal models employed elements of heat exchange that predict physiologic response and incorporate extensive descriptions of the passive system in terms of a steady-state bio-heat equation. In our Institute, a significant database has been collected from human experimental studies and wide clothing systems by which predictive modeling equations can be developed for individuals working in various environments. One model developed takes into consideration different clothing ensembles, varied levels of aerobic fitness in a population, and effects of progressive dehydration to heat stress/exercise. This review encompasses approaches conventionally used in both rational and operational models and presents a comparison between measured and predicted core temperature responses during exercise and environmental exposure often encountered during HAZMAT operations.
