The Effect of Beetroot Extract on Power Output during Submaximal Exercise.

Abstract

Beetroot is a natural source of nitrate which has shown to be an effective ergogenic aid through its effect on pulmonary vasculature and muscle metabolism, positively increasing an individual's athletic performance. The purpose of this study was to investigate whether a six day consecutive ingestion period of beetroot extract supplement would improve athletic performance during a submaximal cycling test in individuals of varying fitness levels. Nine participants were recruited to perform a submaximal exercise test on a cycle ergometer for fifteen minutes with power output recorded for the last three minutes of the test. The participants' resting blood pressure, resting heart rate, active blood pressure and Borg Scale of Perceived Exertion value were also recorded. In this cross-over, placebo-controlled study participants were randomly assigned to either a placebo (vitamin C) or beetroot extract group, performing the exercise tests over a three-week duration including a one week no supplementation interval to allow for a wash out period. Results demonstrated a significant increase in mean power output by 17% (P = 0.017) compared with baseline measurements in the beetroot extract supplementation group. Moreover, resting systolic blood pressure was also significantly reduced by 7.5% (P = 0.001) after the beetroot extract supplementation compared to baseline measurements. Resting heart rate and active blood pressure did not differ significantly after the intervention. This study provides evidence that six-days of beetroot extract supplementation positively affects athletic performance in individuals of varying fitness levels. Keywords: Beetroot extract, Submaximal exercise, Power output, Nitrate (NO3-), Nitric oxide (NO)