Dose-related effects of prolonged NaHCO3 ingestion during high-intensity exercise

Abstract

Purpose: Sodium bicarbonate (NaHCO3) ingestion may prevent exercise-induced perturbations in acid-base balance, thus resulting in performance enhancement. This study aimed to determine whether different levels of NaHCO3 intake influences acid-base balance and performance during high-intensity exercise after 5 d of supplementation. Methods: Twenty-four men (22 +/- 1.7 yr) were randomly assigned to one of three groups (eight subjects per group): control (C, placebo), moderate NaHCO3 intake (MI, 0.3 g(.)kg(-1.)d(-1)), and high NaHCO3 intake (111, 0.5 g(.)kg(-1.)d(-1)). Arterial pH, HCO3-, PO2, PCO2, K+, Na+, base excess (BE), lactate, and mean power (MP) were measured before and after a Wingate test pre- and postsupplementation. Results: HCO3- increased proportionately to the dosage level. No differences were detected in C. Supplementation increased MP (W(.)kg(-1)) in MI (7.36 +/- 0.7 vs 6.73 +/- 1.0) and HI (7.72 +/- 0.9 vs 6.69 +/- 0.6), with HI being more effective than MI. NaHCO3 ingestion resulted postexercise in increased lactate (mmol(.)L(-1)) (12.3 +/- 1.8 vs 10.3 +/- 1.9 and 12.4 +/- 1.2 vs 10.4 +/- 1.5 in MI and HI, respectively), reduced exercise-induced drop of pH (7.305 +/- 0.04 vs 7.198 +/- 0.02 and 7.343 +/- .05 vs 7.2 +/- 0.01 in MI and HI, respectively) and HCO3- (mmol(.)L(-1)) (13.1 +/- 2.4 vs 17.5 +/- 2.8 and 13.2 +/- 2.7 vs 19.8 +/- 3.2 for HCO3 in MI and HI, respectively), and reduced K+ (3.875 +/- 0.2 vs 3.625 +/- 0.3 mmol(.)L(-1) in MI and HI, respectively). Conclusion: NaHCO3 administration for 5 d may prevent acid-base balance disturbances and improve performance during anaerobic exercise in a dose-dependent manner.