The effect of beetroot juice supplementation on repeat-sprint performance in hypoxia.
J Sports Sci. 2018 Jul 30:1-8. Epub 2018 Jul 30. PMID: 30058956
Georgina L Kent
This investigation assessed the effect of dietary nitrate (NO) supplementation, in the form of beetroot juice (BR), on repeat-sprint performance in normoxia and normobaric hypoxia. 12 male team-sport athletes (age 22.3 ± 2.6 y, VO53.1 ± 8.7 mL.kg.min) completed three exercise trials involving a 10 min submaximal warm-up and 4 sets of cycling repeat-sprint efforts (RSE; 9 × 4 s) at sea level (CON), or at 3000 m simulated altitude following acute supplementation (140 mL) with BR (HYP; 13 mmol NO) or NOdepleted BR placebo (HYP). Peak (PPO) and mean (MPO) power output, plus work decrement were recorded during the RSE task, while oxygen consumption (VO) was measured during the warm-up. There were no significant differences observed between HYPand HYPfor PPO or MPO; however, work decrement was reduced in the first RSE set in HYPcompared with HYP. There was a moderate effect for VOto be lower following BR at the end of the 10 min warm-up (ES = 0.50 ± 0.51). Dietary NOmay not improve repeat-sprint performance in hypoxia but may reduce VOduring submaximal exercise. Therefore, BR supplementation may be more effective for performance improvement during predominantly aerobic exercise.