Individualized model of human thermoregulation for the simulation of heat stress response

A population-based dynamic model of human thermoregulation was expanded wit h control equations incorporating the individual person's characteristics ( body surface area, mass, fat%, maximal O-2 uptake, acclimation). These affe ct both the passive (heat capacity, insulation) and active systems (sweatin g and skin blood flow function). Model parameters were estimated from liter ature data. Other data, collected for the study of individual differences { working at relative or absolute workloads in hot-dry [45 degreesC, 20% rela tive humidity (rh)], warm-humid [35 degreesC, 80% rh], and cool [21 degrees C, 50% rh] environments}, were used for validation. The individualized mode l provides an improved prediction [mean core temperature error, -0.21 --> - 0.07 degreesC (P < 0.001); mean squared error, 0.40 --> 0.16 degreesC, (P < 0.001)]. The magnitude of improvement varies substantially with the climat e and work type. Relative to an empirical multiple-regression model derived from these specific data sets, the analytical simulation model has between 54 and 89% of its predictive power, except for the cool climate, in which this ratio is zero. In conclusion, individualization of the model allows im proved prediction of heat strain, although a substantial error remains.