Control of sweating in man after work-induced thermal load and symmetrically applied cooling

To examine the compensatory effects of work-induced thermal load and symmetrically applied local cooling on local sweat rates, two kinds of experiment were carried out on eight male subjects in a climatic chamber: 1) Experiments at 36 degrees C ambient temperature with a work load of about 25 W by the right leg. 2) Experiments at 36 degrees C ambient temperature with a work load of about 25 W by the right leg as in 1., but with additional compensatory cooling of the left leg controlled throughout by heat balance calculations at 75-85 W, equal to the heat produced in the working leg, the necessary air temperature being dependent on local sweat rate. Work load without cooling brought about a significant increase in core temperatures, metabolism, heart rate and local sweat rates. With unchanged local skin temperatures local sweat rate increase was higher in the working leg. Therefore the existence of muscle thermoreceptors should be assumed, the afferent information from which is processed and weighted in a different way to that provided by skin receptors. Work load combined with additional cooling reduced local and mean skin temperatures and heart rate, but had no significant influence on core temperature or metabolism. However, local sweat rate was generally lower in both thighs, with a major reduction in the cooled leg confirming control of local sweat rate by local temperature.(ABSTRACT TRUNCATED AT 250 WORDS)