Sweating and sweat decline of resting men in hot humid environments.

Time courses of the rates of sweating, drippage and evaporation were studied in hot humid environments. Resting subjects wearing only briefs were exposed to humid conditions, before, during and after humid heat acclimation, so that different levels of skin wettedness could be studied on the entire body. In addition, local sweat rate was measured on the right upper limb, which was enclosed in a highly ventilated arm-chamber. Thus, the arm remained drier than the rest of the body surface. The results confirm that sweating efficiency is related to the skin wettedness level, and that the decline in intensity of sweating is linked to maximal inefficient sweat drippage before the onset of hidromeiosis. Comparison of general and local sweat decreases confirms that hidromeiosis originates from skin hydration. However it is likely that some factor related to blood content acts on the hidromeiotic process, at least after humid heat acclimation.