FRIDAY, Aug. 7, 2009 (HealthDay News) -- Beetroot juice can boost physical stamina and increase exercise endurance by up to 16 percent, a new British study shows.
The researchers found that nitrate in beetroot juice reduces oxygen uptake to a degree that can't be achieved by any other means. The findings could benefit endurance athletes, elderly people and those with cardiovascular, respiratory or metabolic diseases, the study authors suggest.
The study included eight men, aged 19 to 38, who drank 500 milliliters a day of organic beetroot juice for six consecutive days. They then completed a series of tests on an exercise bike. The same tests were repeated after the men drank the same amount of a placebo (blackcurrant cordial) for six days.
After drinking the beetroot juice, the men were able to cycle for an average of 11.25 minutes -- 92 seconds longer than after consuming the placebo drink. The men also had a lower resting blood pressure after they drank the beetroot juice, the researchers found.
The study was published Aug. 6 in the Journal of Applied Physiology.
"Our study is the first to show that nitrate-rich food can increase exercise endurance," corresponding author Andy Jones, a professor in the University of Exeter's School of Sport and Health Sciences, said in a news release from the university.
"We were amazed by the effects of beetroot juice on oxygen uptake because these effects cannot be achieved by any other known means, including training. I am sure professional and amateur athletes will be interested in the results of this research. I am also keen to explore the relevance of the findings to those people who suffer from poor fitness and may be able to use dietary supplements to help them go about their daily lives," Jones added.
He and his colleagues don't know the exact mechanism that causes nitrate in beetroot juice to increase stamina, but they suspect that nitrate may turn into nitric oxide in the body, leading to a reduction in oxygen uptake and making exercise less tiring.
The U.S. National Heart, Lung, and Blood Institute offers a guide to physical activity.