Insensible perspiration from the skin under standardized environmental conditions.

The cutaneous insensible perspiration of adult healthy volunteers was measured by a new method based on estimation of the vapour pressure gradient in the air layer immediately adjacent to skin. All measurements were performed at ambient temperatures of 22 degrees, 27 degrees and 30 degrees C and at a relative humidity of 30%. On the basis of the results obtained the total body surface area of the investigated subjects was divided into four different zones with respect to quantitative water loss. The percentage contribution of the different zones to the total cutaneous water loss proved to be fairly independent of the amibent temperature. The average total cutaneous insensible perspiration of a naked resting subject with a body surface area of 1.75 m2 was estimated to be 381 +/- 18, 526 +/- 25 and 695 +/- 35 ml per day (mean values +/- SEE) at an ambient temperature of 22 degrees C, 27 degrees C and 30 degrees C, respectively. By recording the evaporation rate from only three separate measurement points, it was possible to calculate the total cutaneous insensible water loss with good accuracy.