Free flow of sweat due to loss of surface tension at sweat droplets causes water-induced skin wrinkling

Abstract

Water immersion skin wrinkling has long been used as a test for sympathetic nerve function. However, the cause of underlying mechanism remained elusive. In this article, we theoretically investigate a possible cause of the phenomenon by taking various properties of sweating into consideration. The pressure exerted by the surface tension of sweat droplets counterbalances the secretory pressure of sweat glands at the pore. When a hand is immersed in water, sweat droplets easily merge with the water, causing the pressure to drop at the pore. Our calculations, using earlier measurements of secretory pressure, show that the water pressure at the sweat pore will be less than the secretory pressure of sweat glands when the hand is immersed at a shallow depth. The resulting pressure imbalance enables the sweat to flow freely into the water. We believe that there will be an initial vasodilation to feed the excess generation of sweat. Sweat flow continues as long as there is blood flow to the hand. To prevent excessive loss of sweat from the body and to maintain homeostasis, sympathetic nerves trigger vasoconstriction to reduce the blood flow to the hand. The overlying skin wrinkles due to loss of volume under the skin. It is possible that denerved fingers remain in the vasodilation state during immersion due to a lack of sympathetic nerve function.

Physiology Of Drowning: A Review

“…Increased HR may trigger ventricular arrhythmias, potentially hazardous in combination with peripheral vasodilatation and increased blood viscosity (229). The associated dehydration increases likelihood of thrombosis, particularly in the elderly (158,239). HWI drowning is most likely to occur during protracted immersion at high temperature and when leaving the tub (1,117).…”