Effects of beetroot juice treatment on oxygen consumption. Bars represent means ± SD of oxygen consumption, expressed in mL·kg−1·min−1, for a placebo control orange juice treatment and an isocaloric, isovolumetric beetroot juice treatment on separate days in 12 normotensive, young adult, African-American, female university students. The treatments are compared at rest (baseline) and at constant workload power outputs corresponding to 3 submaximal levels of aerobic exercise (40%, 60%, and 80% of each subject’s predetermined peak oxygen consumption (V̇O2peak)).*, Difference between the control and beetroot juice treatments was statistically significant at p < 0.05.