Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans

Beetroot Juice Intake May Improve Exercise Endurance

Keywords:EXERCISE, ENDURANCE - Beetroot Juice, Dietary Nitrates

Reference:“Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans,” Bailey SJ, Jones AM, et al, J Appl Physiol, 2009 Aug 6; [Epub ahead of print]. (Address: Exeter University. E-mail: a.m.jones@exeter.ac.uk ).

Summary:In a double-blind, placebo-controlled, crossover study involving 8 men aged 19-38 years, results indicate that consumption of nitrate-rich beetroot juice may enhance exercise endurance. The participants were randomized to 500 mL per day of either beetroot juice (BR, containing 11.2 mM of nitrate) or a placebo juice (negligible nitrate content) for a period of 6 days, following which the interventions were crossed over for another 6 days. On the last 3 days of each intervention phase, the men completed a series of 'step' moderate-intensity and severe-intensity exercise tests. Dietary nitrate supplementation (beetroot juice) was associated with significantly greater plasma nitrite, significantly lower systolic blood pressure, and reduced muscle fractional O2 extraction, compared with placebo. Additionally, beetroot juice consumption was found to significantly reduce the O2 cost of moderate exercise and increase the time to task failure during severe exercise. Thu s, the authors of this study conclude, “The principal original finding of this investigation is that three days of dietary supplementation with nitrate-rich beetroot juice (which doubled the plasma nitrite) significantly reduced the O2 cost of cycling at a fixed sub-maximal work rate and increased the time to task failure during severe exercise.”