title: Effects of metered versus bolus water consumption on urine production and rehydration.
abstract: This study compared the effects of a rapid bolus and a slower metered water-consumption rate on urine production and postexercise rehydration. Participants (n = 8) dehydrated by 2% body weight through moderate exercise in an environmentally controlled chamber (35 degrees C, 55% relative humidity). Breakfast and lunch were standardized for all participants during each 8-hr data-collection period. Rehydration was performed using a volume of water equal to that lost during exercise either as bolus consumption (100% of volume consumed in 1 hr; BOL) or metered consumption (12.5% of volume every 30 min for 4 hr; MET). Urine volume was used to assess hydration efficiency (water retained vs. water lost) and net fluid balance at 8 hr. Mean urine outputs were 420 ml (MET) and 700 ml (BOL). A paired-samples t test showed that hydration efficiency was greater for MET (75%) than for BOL (55%; p = .018). These data suggest that metered administration was more effective in maintaining fluid balance. These findings suggest that rehydration rate is a factor in fluid-balance response. For situations in which available fluid volume is restricted, greater hydration efficiency is highly desirable.
authors.affiliation: Dept. of Kinesiology and Health Science, Stephen F. Austin State University, Nacogdoches, TX, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Jones
authors.forename: Phil A
authors.initials: PA
authors.lastname: Bishop
authors.forename: James M
authors.initials: JM
authors.lastname: Green
authors.forename: Mark T
authors.initials: MT
authors.lastname: Richardson
mesh_terms: D000328:Adult; D003681:Dehydration / Q000378:metabolism*; D004326:Drinking / Q000502:physiology*; D004573:Electrolytes / Q000097:blood; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D010953:Plasma Volume / Q000187:drug effects / Q000502:physiology; D014563:Urodynamics / Q000187:drug effects / Q000502:physiology*; D014867:Water / Q000008:administration & dosage* / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*
chemical_list: D004573:Electrolytes; D014867:Water