Some Factors Determining the Insensible Perspiration of Man

Regional variations in transepidermal water loss, eccrine sweat gland density, sweat secretion rates and electrolyte composition in resting and exercising humans

“…These equate with respective flows of 42.7, 25.7, 75.9 and 43.4 g.h −1 , assuming a constant body surface area of 1.8 m 2 . Of these, only the second approximates the classical value reported by Benedict and Wardlaw [33] (15 g.h −1 ), as determined from whole-body mass changes. More recent data from six sites, but only three body segments (forehead, forearm, abdomen), are also supportive of these higher values, averaging 0.03 mg.cm −2 .min −1 or 28.9 g.h −1 [48].…”

“…In resting, thermoneutral individuals, whole-body water loss is widely accepted to occur at about 30 g.h −1 in adult males [33], with approximately 50% of this passing through the skin [34]; transepidermal loss. This gradual water flux is dependent, to a slight extent, upon the thickness of the stratum corneum (being smaller for thicker tissue layers within each region [35,36]), the size of the intervening corneocytes (inverse relationship [29]), local tissue temperature (greater when warmed [37-39]), the boundary-layer water vapour pressure (greater at lower vapour pressures [13,39,40]) and even posture (greater when upright [33]).…”

“…This gradual water flux is dependent, to a slight extent, upon the thickness of the stratum corneum (being smaller for thicker tissue layers within each region [35,36]), the size of the intervening corneocytes (inverse relationship [29]), local tissue temperature (greater when warmed [37-39]), the boundary-layer water vapour pressure (greater at lower vapour pressures [13,39,40]) and even posture (greater when upright [33]). However, it is not influenced by changes in cutaneous blood flow, unless there is a corresponding elevation in local tissue temperature [13].…”

The Relationship Between Insensible Water Loss and Heat Production in Patients With Hypothyroidism Compared With Normal Subjects 1

“…control group than has been found in normal subjects under strictly basal conditions by others (1, 2, 6). Benedict and Wardlaw (8) in four experiments found the insensible water loss to increase on an average of 20 per cent in the sitting position as compared with the lying position; no simultaneous metabolic measurements were made, but the increase in water loss seemed somewhat higher than the expected increase in metabolism (8).…”

“…Jores (11) and Dieckhoff (12), however, found that the increase in metabolism following a protein meal was not always associated with a corresponding increase in insensible water loss, in fact in certain experiments the insensible loss did not increase at all when the metabolism increased by as much as 30 per cent. Furthermore, results of other investigators have revealed that the heat lost by vaporization in sleep (8,9,13) and on activity (7), even when unaccompanied by sensible perspiration, may not bear the same relation to total heat production as obtains under basal conditions.…”