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

Abstract

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 (VO 2 max 65 mL·kg·min -1 ) male cyclists completed four × 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.

Time to Optimize Supplementation: Modifying Factors Influencing the Individual Responses to Extracellular Buffering Agents

“…Discrepancies could be due to timing and subsequent increases in circulating bicarbonate. Mean bicarbonate increases in Gough et al ( 48 ) were +6.5 ± 1.3 mmol·L −1 , which is higher than the approximate +3 mmol·L −1 ( 78 ) and +5 mmol·L −1 ( 79 ) shown 150 and 100 min following supplement ingestion in the other studies. Despite these initial positive results, no data exist directly comparing exercise performed at the moment of peak circulating bicarbonate to a standardized time (e.g., 60 min) following supplementation in the same participants.…”

Caffeine and Bicarbonate for Speed. A Meta-Analysis of Legal Supplements Potential for Improving Intense Endurance Exercise Performance

“…We terminated our study search in April 2016 but the field of ergogenic supplements continues to evolve. Recently, studies has been published showing no effect on intense endurance performance from both bicarbonate (Callahan et al, 2016) and nitrate (Callahan et al, 2016) supplementation whereas caffeine has resulted in both unchanged (Cordingley et al, 2016) and improved performance (Boyett et al, 2016). A number of the included studies in the current meta-analysis also reported negative findings, so to what extent an actual publication bias toward positive results exits remains unknown.…”

Nitrate supplementation improves physical performance specifically in non-athletes during prolonged open-ended tests: a systematic review and meta-analysis

“…The χ 2 test showed a different distribution among the PL (P = 0•002). Rimer et al (73) Rimer et al (2) (72) Lane et al Glaister et al (60) Peeling et al (1) (71) McQuillan et al (8) 67Martin et al (3) (66) Bescós et al (2) (25) Callahan et al (1) (59) Callahan et al Muggeridge et al (2) (69) McQuillan et al (1) (68) Bescós et al (1) (25) Thompson et al (2) Lowings et al (65) Cermak et al (2)…”

“…(2) (21) Cermak et al (1) (21) Nyakayiru et al (1) (50) Wilkerson et al (1) (76) Callahan et al (1) (59) Callahan et al…”