Effect Of B-Alanine Supplementation, With And Without Sodium Bicarbonate, On High-Intensity Cycling Capacity.

Abstract

PURPOSE: To examine the effect of b-alanine supplementation, with and without sodium bicarbonate, on high-intensity cycling capacity. METHODS: Twelve males (age 25±3 yrs; height 1.79±0.05 m; body mass 81.2±9.8 kg) completed 4 cycling capacity tests at 110% of maximum power (CCT110%) to determine total work done (TWD). Subjects were equally assigned to one of 2 supplementation groups (placebo or b-alanine); each performed the CCT110%, in a randomised order, twice pre-supplementation (with and without sodium bicarbonate) and twice post supplementation (with and without sodium bicarbonate). The study comprised four double-blind experimental conditions: placebo + placebo (PP), placebo + sodium bicarbonate (PSB), b-alanine + placebo (BAP) and b-alanine + sodium bicarbonate (BASB). Blood lactate and bicarbonate were determined at rest, pre-exercise, post-exercise and 5 minutes post-exercise. Data were analysed using a three-way repeated measures ANOVA. RESULTS: TWD during the CCT110% was increased in all conditions post-supplementation, with the largest increases being shown with b-alanine (+7.9% PP, +4.1% PSB, +11.1% BAP and +17.6% BASB). Supplementation with BASB resulted in significantly greater TWD during the CCT110% than during the other conditions (P < 0.05). Blood lactate concentrations were significantly elevated following exercise and remained so after 5 minutes of recovery (P < 0.001). Blood bicarbonate concentrations were elevated pre-exercise in PSB (pre: 31.06±1.13 mmol·L-1, post: 31.27±0.70 mmol·L-1) and BASB (pre: 30.40±1.22 mmol·L-1; post: 29.73±2.29 mmol·L-1) but not in PP (pre: 24.91±0.83 mmol·L-1; post: 25.20±1.35 mmol·L-1) or BAP (pre: 25.10±1.41 mmol·L-1; post: 24.83±1.37 mmol·L-1). CONCLUSIONS: The results suggest that b-alanine supplementation improved high-intensity cycling capacity in agreement with previously published results. However, this was further improved by co-ingestion with sodium bicarbonate. As such, those individuals engaged in high-intensity exercise, which is limited by H+ accumulation in the muscle and blood, might benefit from supplementation with b-alanine and sodium bicarbonate.