Sweating response in man during transient rises of air temperature

Nude men were exposed to neutral environments (Ta = 28 degrees C, Pw = 20 mbar) changing to warm environments (Ta = 50 degrees C, Pw = 20 mbar). The transient period from neutral to warm environment lasted 4 min (dTA/DT = 5.50 degrees C/min) or 20 min (DTa/dt = 1.10 degrees C/min) or 40 min (dTa/dt = 0.55 degrees C/min) or 60 min (dTa/dt = 0.37 degrees C/min). Continuous measurements were made of rectal and mean skin temperatures and of body weigth loss. Sweating started before appreciable variation in rectal temperature. Onset of sweating could be explained by a peripheral proportional and rate control. Unsteady-state sweating can be predicted by summated stimulation of skin and rectal temperatures. This stimulation could be increased for some subjects by a multiplicative effect due to differences in local skin temperatures. This multiplicative effect occurred during the first transient period.