Thermoregulatory heat production in man: prediction equation based on skin and core temperatures.

The relationship of metabolic rate to skin and core temperatures was measured in eight subjects cooled in 10 degrees C water. Reference core temperatures, based on the tympanic and rectal sites, were 41.0 and 41.4 degrees C, respectively. Reference mean skin temperatures were 41.8 and 42.2 degrees C when determined in relation to tympanic and rectal temperatures, respectively. These results enabled construction of equations for predicting the steady-state metabolic rate (MR, W-kg-1) of nonexercising man according to thermal inputs from the skin (Tsk) and core (Tty or Tre) MR = 0.0356(Tsk - 41.8)(Tty - 41.0) or, MR = 0.0314(Tsk - 42.2)(Tre - 41.4). Each equation was limited by the low level of basal metabolic rate (1.1 W-kg-1) and by the high level of peak metabolic rate (6.4 W-kg-1). Evaluation of these equations showed satisfactory agreement with previous observations and concepts on the regulation of heat production in man.