Single and Combined Effects of Beetroot Crystals and Sodium Bicarbonate on 4-km Cycling Time Trial Performance

When ingested alone, beetroot juice and sodium bicarbonate are ergogenic for high-intensity exercise performance. This study sought to determine the independent and combined effects of these supplements. Eight endurance trained (VO2max 65 mL.kg.min(-1)) male cyclists completed four x 4-km time trials (TT) in a doubleblind Latin square design supplementing with beetroot crystals (BC) for 3 days (15 g.day(-1) + 15 g 1 h before TT, containing 300 mg nitrate per 15 g), bicarbonate (Bi 0.3 g. kg(-1) body mass [ BM] in 5 doses every 15 min from 2.5 h before TT); BC+ Bi or placebo (PLA). Subjects completed TTs on a Velotron cycle ergometer under standardized laboratory conditions. Plasma nitrite concentrations were significantly elevated only in the BC+ Bi trial before the TT (1520 +/- 786 nmol.L-1) compared with baseline (665 +/- 535 nmol.L-1, p = .02) and the Bi and PLA conditions (Bi: 593 +/- 203 nmol.L-1, p < .01; PLA: 543 +/- 369 nmol.L-1, p < .01). Plasma nitrite concentrations were not elevated in the BC trial before the TT (1102 +/- 218 nmol.L-1) compared with baseline (975 +/- 607 nmol.L-1, p > .05). Blood bicarbonate concentrations were increased in the BC+ Bi and Bi trials before the TT (BC+Bi: 30.9 +/- 2.8 mmol.L-1; Bi: 31.7 +/- 1.1 mmol.L-1). There were no differences in mean power output (386-394 W) or the time taken to complete the TT (335.8-338.1 s) between any conditions. Under the conditions of this study, supplementation was not ergogenic for 4-km TT performance.