The effect of acute pomegranate extract supplementation on oxygen uptake in highly-trained cyclists during high-intensity exercise in a high altitude environment

摘要

BackgroundRecent research has indicated that pomegranate extract (POMx) may improve performance during aerobic exercise by enhancing the matching of vascular oxygen (O₂) provision to muscular requirements. POMx is rich in ellagitannin polyphenols and nitrates (NO₃?), which are both associated with improvements in blood flow and O₂ delivery. Primarily, this study aimed to determine whether POMx improves performance in a cycling time trial to exhaustion at 100%VO_2max (TTE100%) in highly-trained cyclists. In addition, we investigated if the O₂ cost (VO₂) of submaximal exercise was lower with POMx, and whether any changes were greater at high altitude where O₂ delivery is impaired. MethodsEight cyclists exercised at three submaximal intensities before completing a TTE100% at sea-level (SEA) and at 1657?m of altitude (ALT), with pre-exercise consumption of 1000?mg of POMx or a placebo (PLAC) in a randomized, double-blind, crossover design. Data were analysed using a three way (treatment x altitude x intensity) or two-way (treatment x altitude) repeated measures ANOVA with a Fisher’s LSD post-hoc analysis. Significance was set at p ≤?0.05. The effect size of significant interactions was calculated using Cohen’s d. ResultsTTE100% performance was reduced in ALT but was not influenced by POMx ( p >?0.05). Plasma NO₃? were 10.3?μmol greater with POMx vs. PLAC (95% CI, 0.8, 19.7, F _1,7?=?7.83, p 2 measured at five minutes into the TTE100% was significantly increased in ALTPOMx vs. ALTPLAC (+3.8?ml.min?1kg?1, 95% CI, ?5.7, 9.5, F_1,7?=?29.2, p =?0.001, ES?=?0.6) but unchanged in SEAPOMx vs. SEAPLAC ( p >?0.05). Submaximal VO₂ values were not affected by POMx ( p ≥?0.05). ConclusionsThe restoration of SEA VO₂ values at ALT is likely driven by the high polyphenol content of POMx, which is proposed to improve nitric oxide bioavailability. Despite an increase in VO₂, no change in exercise performance occurred and therefore this study does not support the use of POMx as an ergogenic supplement.