title: A Sodium Drink Enhances Fluid Retention During 3 Hours of Post-Exercise Recovery When Ingested With a Standard Meal.
abstract: The purpose of this study was to examine the efficacy of water and a 50 mmol/L NaCl solution on postexercise rehydration when a standard meal was consumed during rehydration. Eight healthy participants took part in two experimental trials during which they lost 1.5 ± 0.4% of initial body mass via intermittent exercise in the heat. Participants then rehydrated over a 60-min period with water or a 50 mmol/L NaCl solution in a volume equivalent to 150% of their body mass loss during exercise. In addition, a standard meal was ingested during this time which was equivalent to 30% of participants predicted daily energy expenditure. Urine samples were collected before and after exercise and for 3 hr after rehydration. Cumulative urine volume (981 ± 458 ml and 577 ± 345 mL; p = .035) was greater, while percentage fluid retained (50 ± 20% and 70 ± 21%; p = .017) was lower during the water compared with the NaCl trial respectively. A high degree of variability in results was observed with one participant producing 28% more urine and others ranging from 18-83% reduction in urine output during the NaCl trial. The results of this study suggest that after exercise induced dehydration, the ingestion of a 50 mmol/L NaCl solution leads to greater fluid retention compared with water, even when a meal is consumed postexercise. Furthermore, ingestion of plain water may be effective for maintenance of fluid balance when food is consumed in the rehydration period.
authors.forename: Gethin H
authors.initials: GH
authors.lastname: Evans
authors.forename: Jennifer
authors.initials: J
authors.lastname: Miller
authors.forename: Sophie
authors.initials: S
authors.lastname: Whiteley
authors.forename: Lewis J
authors.initials: LJ
authors.lastname: James
mesh_terms: D001628:Beverages; D003681:Dehydration; D004435:Eating; D015444:Exercise; D005260:Female; D005440:Fluid Therapy; D006358:Hot Temperature; D006801:Humans; D008297:Male; D015532:Rehydration Solutions / Q000008:administration & dosage; D012964:Sodium / Q000008:administration & dosage* / Q000652:urine; D064133:Sports Nutritional Physiological Phenomena; D013546:Sweating; D014867:Water / Q000008:administration & dosage*; D014882:Water-Electrolyte Balance; D055815:Young Adult
chemical_list: D015532:Rehydration Solutions; D014867:Water; D012964:Sodium
keywords: hypohydration; net fluid balance; recovery