Rehydration with Fluid of Varying Tonicities: Effects on Fluid Regulatory Hormones and Exercise Performance in the Heat; Journal article

摘要

Rehydration with fluid of varying tonicities: effects on fluid regulatory hormones and exercise performance in the heat. J Appl Physiol 102: 1899 1905, 2007. First published February 22, 2007; doi:10.1152/japplph ysiol.00920.2006. This study examined the effects of rehydration (Rehy) with fluids of varying tonicities and routes of administration after exercise-induced hypohydration on exercise performance, fluid regulatory hormone responses, and cardiovascular and thermoregulatory strain during subsequent exercise in the heat. On four occasions, eight men performed an exercise-dehydration protocol of approximately 185 min (33 C) to establish a 4% reduction in body weight. Following dehydration, 2% of the fluid lost was replaced during the first 45 min of a 100-min rest period by one of three random Rehy treatments (0.9% saline intravenous; 0.45% saline intravenous; 0.45% saline oral) or no Rehy (no fluid) treatment. Subjects then stood for 20 min at 36 C and then walked at 50% maximal oxygen consumption for 90 min. Subsequent to dehydration, plasma Na , osmolality, aldosterone, and arginine vasopressin concentrations were elevated.