Published in:
Open Access 01-12-2013 | Research article
Multiday acute sodium bicarbonate intake improves endurance capacity and reduces acidosis in men
Published in: Journal of the International Society of Sports Nutrition | Issue 1/2013
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Background
The purpose was to investigate the effects of one dose of NaHCO3 per day for five consecutive days on cycling time-to-exhaustion (Tlim) at ‘Critical Power’ (CP) and acid–base parameters in endurance athletes.
Methods
Eight trained male cyclists and triathletes completed two exercise periods in a randomized, placebo-controlled, double-blind interventional crossover investigation. Before each period, CP was determined. Afterwards, participants completed five constant-load cycling trials at CP until volitional exhaustion on five consecutive days, either after a dose of NaHCO3 (0.3 g·kg-1 body mass) or placebo (0.045 g·kg-1 body mass NaCl).
Results
Average Tlim increased by 23.5% with NaHCO3 supplementation as compared to placebo (826.5 ± 180.1 vs. 669.0 ± 167.2 s; P = 0.001). However, there was no time effect for Tlim (P = 0.375). [HCO3-] showed a main effect for condition (NaHCO3: 32.5 ± 2.2 mmol·l-1; placebo: 26.2 ± 1.4 mmol·l-1; P < 0.001) but not for time (P = 0.835). NaHCO3 supplementation resulted in an expansion of plasma volume relative to placebo (P = 0.003).
Conclusions
The increase in Tlim was accompanied by an increase in [HCO3-], suggesting that acidosis might be a limiting factor for exercise at CP. Prolonged NaHCO3 supplementation did not lead to a further increase in [HCO3-] due to the concurrent elevation in plasma volume. This may explain why Tlim remained unaltered despite the prolonged NaHCO3 supplementation period. Ingestion of one single NaHCO3 dose per day before the competition during multiday competitions or tournaments might be a valuable strategy for performance enhancement.
Trial registration
Trial registration: ClinicalTrials.gov IdentifierNCT01621074