EXETER, England—Consumption of a nitrate-rich juice reduced the energy depletion associated with muscle exertion, and allowed greater exercise tolerance, according to results of a small human trial (J Appl Physiol. ePub 13 May 2010. DOI:10.1152/japplphysiol.00046.2010). Researchers from Exeter University and the University of Exeter enrolled seven men in a randomized, double-blind, crossover trial to consume 500 mL per day of beetroot juice, providing 5.1 mmol of dietary nitrate (NO3-), or placebo for six consecutive days. The subjects completed a series of low- and high-intensity step exercise tests on the final three days to determine muscle metabolic and pulmonary oxygen uptake (VO2).
Consumption of beetroot juice significantly increased plasma nitrite. Beetroot juice attenuated reductions in muscle phosphocreatine (PCr) concentration during low-intensity exercise; it also reduced amplitudes of PCr concentration reductions and improved time to exhaustion. Total ATP turnover rate during exercise was also less for subjects taking beetroot juice.
