Effect of Sodium Bicarbonate and Beta-Alanine on Repeated Sprints During Intermittent Exercise Performed in Hypoxia

Abstract

To investigate the separate and combined effects of sodium bicarbonate and beta-alanine supplementation on repeated sprints during simulated match play performed in hypoxia. Study A: 20 recreationally active participants performed two trials following acute supplementation with either sodium bicarbonate (0.3 g·kg-1BM) or placebo (maltodextrin). Study B: 16 recreationally active participants were supplemented with either a placebo or beta-alanine for 5 weeks (6.4 g·day-1 for 4 weeks, 3.2 g·day-1 for 1 week), and performed one trial before supplementation (with maltodextrin) and two following supplementation (with sodium bicarbonate and maltodextrin). Trials consisted of 3 sets of 5 × 6 s repeated sprints performed during a football specific intermittent treadmill protocol performed in hypoxia (15.5% O2). Mean (MPO) and peak (PPO) power output were recorded as the performance measures. Study A: Overall MPO was lower with sodium bicarbonate than placebo (p = .02, 539.4 ± 84.5 vs. 554.0 ± 84.6 W), although there was no effect across sets (all p > .05). Study B: There was no effect of beta-alanine, or cosupplementation with sodium bicarbonate, on either parameter, although there was a trend toward higher MPO with sodium bicarbonate (p = .07). The effect of sodium bicarbonate on repeated sprints was equivocal, although there was no effect of beta-alanine or cosupplementation with sodium bicarbonate. Individual variation may have contributed to differences in results with sodium bicarbonate, although the lack of an effect with beta-alanine suggests this type of exercise may not be influenced by increased buffering capacity.