Fluid Replacement and Heat Stress, 1993
Pp. 161-167. Washington, D.C.
National Academy Press
Barbara J. Rolls1
People consume fluids in response to a variety of physiological, psychological, and environmental stimuli. In this paper, I discuss some of the physiological changes that can affect fluid intake in man and why people drink spontaneously when they have free access to water. The sensations accompanying dehydration are also considered, as is rehydration and its accuracy in restoring fluid deficits. Finally, the effects of palatability of the availabel fluids on thirst satisfaction and consumption are discussed.
During fluid restriction, both the cellular and extracellular body fluid compartments are depleted. Changes in both compartments are associated with thirst and drinking. There is clear experimental evidence that dehydration of the cellular compartment is a potent thirst stimulus. For example, the effects of double-blind intravenous infusions of hypertonic saline (0.45 M) and isotonic saline (0.15 M) were compared in seven healthy young men (Phillips et al., 1985b). Only the hypertonic saline significantly increased
Barbara J. Rolls, The Pennsylvania State University, 104 Benedict House, University Park, PA 16802-2311