title: The quantification of body fluid allostasis during exercise.
abstract: The prescription of an optimal fluid intake during exercise has been a controversial subject in sports science for at least the past decade. Only recently have guidelines evolved from 'blanket' prescriptions to more individualised recommendations. Currently the American College of Sports Medicine advise that sufficient fluid should be ingested to ensure that body mass (BM) loss during exercise does not exceed >2 % of starting BM so that exercise-associated medical complications will be avoided. Historically, BM changes have been used as a surrogate for fluid loss during exercise. It would be helpful to accurately determine fluid shifts in the body in order to provide physiologically appropriate fluid intake advice. The measurement of total body water via D2O is the most accurate measure to detect changes in body fluid content; other methods, including bioelectrical impedance, are less accurate. Thus, the aim of this review is to convey the current understanding of body fluid allostasis during exercise when drinking according to the dictates of thirst (ad libitum). This review examines the basis for fluid intake prescription with the use of BM, the concepts of 'voluntary and involuntary dehydration' and the major routes by which the body gains and loses fluid during exercise.
authors: UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, 3rd Floor, Sports Science Institute of South Africa, Boundary Road, Newlands, Cape Town, Western Cape, South Africa, nicholas.tam@uct.ac.za.
authors: Nicholas
authors: N
authors: Tam
authors: Timothy D
authors: TD
authors: Noakes
mesh_terms: D052636:Allostasis / Q000502:physiology*; D001826:Body Fluids / Q000502:physiology*; D003681:Dehydration / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D014882:Water-Electrolyte Balance / Q000502:physiology*
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