title: Sodium-induced hyperhydration decreases urine output and improves fluid balance compared with glycerol- and water-induced hyperhydration.
abstract: Before 2010, which is the year the World Anti-Doping Agency banned its use, glycerol was commonly used by athletes for hyperhydration purposes. Through its effect on osmoreceptors, we believe that sodium could prove a viable alternative to glycerol as a hyperhydrating agent. Therefore, this study compared the effects of sodium-induced hyperhydration (SIH), glycerol-induced hyperhydration (GIH) and water-induced hyperhydration (WIH) on fluid balance responses. Using a randomized, double-blind and counterbalanced protocol, 17 men (21 ± 3 years, 64 ± 6 kg fat-free mass (FFM)) underwent three 3-h hyperhydration protocols during which they ingested, over the first 60-min period, 30 mL/kg FFM of water with (i) an artificial sweetener (WIH); (ii) an artificial sweetener + 7.45 g/L of table salt (SIH); or (iii) an artificial sweetener + 1.4 g glycerol/kg FFM (GIH). Changes in body weight (BW), urine production, fluid retention, hemoglobin, hematocrit, plasma volume, and perceptual variables were monitored throughout the 3-h trials. After 3 h, SIH was associated with significantly (p < 0.05) lower hemoglobin, hematocrit (SIH: 43.1% ± 2.8%; GIH: 44.9% ± 2.4%), and urine production, as well as greater BW, fluid retention (SIH: 1144 ± 294 mL; GIH: 795 ± 337 mL), and plasma volume (SIH: 11.9% ± 12.0%; GIH: 4.0% ± 6.0%) gains, compared with GIH and WIH. No significant differences in heart rate or abdominal discomfort were observed between treatments. In conclusion, our results indicate that SIH is a superior hyperhydrating technique than, and proves to be a worthwhile alternative to, GIH.
authors.affiliation: a Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC J1H 4C4, Canada.
authors.forename: Félix A
authors.initials: FA
authors.lastname: Savoie
authors.forename: Tommy
authors.initials: T
authors.lastname: Dion
authors.forename: Audrey
authors.initials: A
authors.lastname: Asselin
authors.forename: Eric D B
authors.initials: ED
authors.lastname: Goulet
mesh_terms: D000328:Adult; D001628:Beverages; D003681:Dehydration / Q000517:prevention & control; D004300:Doping in Sports; D004311:Double-Blind Method; D004326:Drinking; D005990:Glycerol / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009846:Oliguria / Q000209:etiology*; D010953:Plasma Volume; D012720:Severity of Illness Index; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage / Q000009:adverse effects; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000009:adverse effects*; D014869:Water Intoxication / Q000097:blood / Q000209:etiology* / Q000503:physiopathology / Q000652:urine; D014882:Water-Electrolyte Balance; D014883:Water-Electrolyte Imbalance / Q000209:etiology / Q000517:prevention & control; D015430:Weight Gain; D055815:Young Adult
chemical_list: D017673:Sodium Chloride, Dietary; D012982:Sodium, Dietary; D005990:Glycerol
keywords: dehydration; déshydratation; fluid balance; hydratation; hydration; overhydration; sel de table; surhydratation; table salt; équilibre hydrique