Beetroot juice and exercise: pharmacodynamic and dose-response relationships.

140 and 280 ml beetroot juice reduced the steady-state oxygen (O2) uptake during moderate-intensity exercise by 1.7% (P = 0.06) and 3.0% (P < 0.05), whereas time-to-task failure was extended by 14% and 12% (both P < 0.05), respectively, compared with placebo