Regional and Individual Variations in the Function of the Human Eccrine Sweat Gland

Derived values for sodium concentration of the precursor fluid, free water clearance and counts of the number of active sweat glands were determined on the forehead, forearm and back of 14 subjects. Maximal sweat rate per gland and maximal free water clearance per gland were also calculated. The sodium concentration of the precursor fluid averaged 140 mEq/L. The large variations among our subjects in the maximal sweat rate (SR max) per m2 and maximal free water clearance (FWC max) per m2 depended mainly on differences in the functional capacity of individual sweat glands rather than in differences in population. However, regional variations in SR max per m2 and FWC max per m2 in each subject depended largely on differences in the population of active sweat glands. A significant correlation was found between secretory (SR max per gland) and reabsorptive capacity (FWC max per gland)