Influence of beetroot juice supplementation on intermittent exercise performance

Purpose This study tested the hypothesis that nitrate (NO 3 − ) supplementation would improve performance during high-intensity intermittent exercise featuring different work and recovery intervals. Method Ten male team-sport players completed high-intensity intermittent cycling tests during separate 5-day supplementation periods with NO 3 − -rich beetroot juice (BR; 8.2 mmol NO 3 − day −1 ) and NO 3 − -depleted beetroot juice (PL; 0.08 mmol NO 3 − day −1 ). Subjects completed: twenty-four 6-s all-out sprints interspersed with 24 s of recovery (24 × 6-s); seven 30-s all-out sprints interspersed with 240 s of recovery (7 × 30-s); and six 60-s self-paced maximal efforts interspersed with 60 s of recovery (6 × 60-s); on days 3, 4, and 5 of supplementation, respectively. Result Plasma [NO 2 − ] was 237 % greater in the BR trials. Mean power output was significantly greater with BR relative to PL in the 24 × 6-s protocol (568 ± 136 vs. 539 ± 136 W; P 0.05). The increase in blood [lactate] across the 24 × 6-s and 7 × 30-s protocols was greater with BR ( P 0.05). Conclusion BR might be ergogenic during repeated bouts of short-duration maximal-intensity exercise interspersed with short recovery periods, but not necessarily during longer duration intervals or when a longer recovery duration is applied. These findings suggest that BR might have implications for performance enhancement during some types of intermittent exercise.