Heat strain models applicable for protective clothing systems: comparison of core temperature response

R. R. Gonzalez 1 , T. M. McLellan 2 , W. R. Withey 3 , S. K. Chang 1 , and K. B. Pandolf 1 1 US Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760-5007; 2 Defence and Civil Institute of Environmental Medicine, North York, Ontario, Canada M3M 3B9; and 3 Centre for Human Sciences, Defence Research Agency, Farnborough, Hampshire GU146TD, United Kingdom Received 22 October 1996; accepted in final form 12 May 1997. Gonzalez, R. R., T. M. McLellan, W. R. Withey, S. K. Chang, and K. B. Pandolf. Heat strain models applicable for protective clothing systems: comparison of core temperature response. J. Appl. Physiol. 83(3): 1017-1032, 1997. Core temperature (T c ) output comparisons were analyzed from thermal models applicable to persons wearing protective clothing. The two models evaluated were the United States (US) Army Research Institute of Environmental Medicine (USARIEM) heat strain experimental model and the United Kingdom (UK) Loughborough (LUT25) model. Data were derived from collaborative heat-acclimation studies conducted by three organizations and included an intermittent-work protocol (Canada) and a continuous-exercise/heat stress protocol (UK and US). Volunteers from the US and the UK were exposed to a standard exercise/heat stress protocol (ambient temperature 35°C/50% relative humidity, wind speed 1 m/s, level treadmill speed 1.34 m/s). Canadian Forces volunteers did an intermittent-work protocol (15 min moderate work/15 min rest at ambient temperature of 40°C/30% relative humidity, wind speed 0.4 m/s). Each model reliably predicted T c responses (within the margin of error determined by 1 root mean square deviation) during work in the heat with protective clothing. Models that are analytically similar to the classic Stolwijk-Hardy model serve as robust operational tools for prediction of physiological heat strain when modified to incorporate clothing heat-exchange factors. heat acclimation; exercise; clothing heat exchange; core temperature; thermal models 0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society