Dehydration and Survivability in Warm Shelters

摘要

The physiological basis for dehydration symptoms is discussed in terms of the factors influencing moisture loss from skin and lungs by diffusion, sweat loss, and urinary output. Normal water and salt balance is shown to be achieved by ingestion of a surplus and excretion of the excess over needs; there is an obligatory or essential output of urine and an unavoidable diffusion loss which sets the minimum safe intake level for healthy persons. Immediate acute effects are seen as soon as sweating causes a net deficit of water larger than 1% of the initial body weight or a salt deficit of 0.5 grams per kilogram of body weight. A biothermal analysis of the interactions between the physical processes of heat and mass transfer at the body surface and the physiological process of sweat production as a response to temperature stimuli reveals why differences between individuals are of paramount importance in the unique conditions of a warm crowded shelter. (Author)