Two new predictive neural network models are reported to estimate (i) core temperature and heart rate, and (ii) time tolerance limits, for subjects exercising in heavy clothing. Although limited to young fit males, the models account for individual variability, and are applicable over a wide range of warm environments and heavy impermeable clothing levels. The relative importance of relevant subject anthropomorphic parameters, environmental parameters, and work rates on the subject’s tolerance time to uncompensable heat stress can also be evaluated via a proposed sensitivity analysis. Among the anthropometric variables, weight was the most relevant to prediction of time tolerance limits. Correlation analyses show that for a group of fit and acclimatized young males, final heart rate was the most significant predictor of time tolerance limit, while final core temperature was not.

Units: I-P