Loss of Minerals Through the Skin of Normal Humans When Sweating Is Avoided

Abstract

Water is constantly vaporizing from the human skin surface as an important part of the heat regulatory mechanism. There are two sources for water to be vaporized: there is always vaporization which occurs as a result of the waterrich human mass existing in a relatively dry atmosphere. Water lost in this way is spoken of as " insensible loss of water." When the amount of heat carried away by this process is insufficient to maintain the homeothermic state, an additional supply of water is pumped onto the surface of the skin by the sweat glands to aid in the cooling process.There have been many analyses of sweat; and quantitative studies of water and minerals lost through the skin during sweating have also been made (1,2, 3,4,5,6). Usually in studies of the latter type, one does not know how much of the total loss of water and inorganic salts is from the sweat glands. There is, in the literature, insufficient data regarding the amount of minerals lost through the skin when sweating is avoided. Mention of the most noteworthy of such data follows. McCance (7) in his studies of sodium chloride deficiency in man has taken into account the loss of minerals and nitrogen in the " insensible perspiration" both during salt restriction and recovery. Cole and Curtis (8) have measured the iodine lost through the skin in some of their iodine balance studies. Swanson and Iob (9) measured the cutaneous loss of some inorganic elements in babies 2 to 24 weeks old, and although the subjects were kept in rooms with the temperature maintained almost constant between 75 and 78°F., the elimination of elements "in sweat " is reported. These workers determined the daily loss of sodium, potassium, calcium, phosphorus and chlorides and found that the amount of potassium lost through the skin was more than 30 per cent of the " retention " calculated in the usual manner.Neglecting loss through the skin caused considerable error in the sodium and chloride balances also, but the calcium and phosphorus losses through the skin were negligible.With the exception of the work of McCance (7) none of the literature cited gives us any information regarding the cutaneous loss of minerals from the healthy adult man who is not sweating. We have therefore conducted the following investigation in order to obtain such information. EXPERIMENTALThe subjects for the experiments were two healthy adult men who went about their usual laboratory duties with special precautions only to keep themselves cool enough to prevent sweating. Special clothing worn during the experiment consisted of medium weight cotton underwear and socks which had previously been thoroughly washed in distilled water until free of chloride. This clothing covered the entire body with the exceptions of the hands, head and neck. No special precautions were taken with the outer clothing except that new shoes were worn. Food and water were uncontrolled except that during the second experiment on Subject B and for the three preceding days the intake of sodium chloride was rigidly restricted.After ...

Electrolyte Balances During Artificial Fever With Special Reference to Loss Through the Skin 1

“…This bath water and the extracts of the clothing were concentrated and analysed. The amount of salt recovered was of the same order of magnitude (Table V) as that reported by others (16,17). Determination of the electrolyte content of the sweat during fever was carried out in essentially the same manner.…”

Electrolyte Equilibrium During Mercurial Diuresis 12

“…Deviation of the two curves from each other indicates unmeasured losses through the skin, losses of intracellular fluid, or shifts of sodium into or out of the intracellular compartment. Minimal sweating occurred during these experiments so that losses of sodium through the skin were probably about 5 to 10 mEq./day (10,11).…”

Metabolic and Renal Studies in Chronic Potassium Depletion Resulting From Overuse of Laxatives 12

“…Little or no sweat-ing occurred during these experiments so that unmeasured losses of sodium through the skin were probably only 5 to 10 mEq. per day (16).…”