Science Daily (Aug. 7, 2009) — Drinking beetroot juice boosts your stamina and could help you exercise for up to 16% longer. A University of Exeter led-study shows for the first time how the nitrate contained in beetroot juice leads to a reduction in oxygen uptake, making exercise less tiring.
The study reveals that drinking beetroot juice reduces oxygen uptake to an extent that cannot be achieved by any other known means, including sports training.
The research team believes that the findings could be of great interest to endurance athletes. They could also be relevant to elderly people or those with cardiovascular, respiratory or metabolic diseases.
The research team conducted their study with eight men aged between 19 and 38. They were given 500ml per day of organic beetroot juice for six consecutive days before completing a series of tests, involving cycling on an exercise bike. On another occasion, they were given a placebo of blackcurrant cordial for six consecutive days before completing the same cycling tests.
After drinking beetroot juice the group was able to cycle for an average of 11.25 minutes, which is 92 seconds longer than when they were given the placebo. This would translate into an approximate 2% reduction in the time taken to cover a set distance. The group that had consumed the beetroot juice also had lower resting blood pressure.
The researchers are not yet sure of the exact mechanism that causes the nitrate in the beetroot juice to boost stamina. However, they suspect it could be a result of the nitrate turning into nitric oxide in the body, this gas keeps the blood vessels open and relaxed and keeps blood pressure down, reducing the oxygen cost of exercise.
The research was carried out by the University of Exeter and Peninsula Medical School and published in the Journal of Applied Physiology. The research team now hopes to conduct further studies to try to understand in more detail the effects of nitrate-rich foods on exercise physiology.
Corresponding author of the study, Professor Andy Jones of the University of Exeter's School of Sport and Health Sciences, said:
"Our study is the first to show that nitrate-rich food can increase exercise endurance. 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."
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Beetroot juice has been shown to lower blood pressure and thus help prevent cardiovascular problems. Research published in the American Heart Association journal Hypertension showed drinking 500 ml of beetroot juice led to a reduction in blood pressure within one hour. The reduction was more pronounced after three to four hours, and was measurable up to 24 hours after drinking the juice. The effect is attributed to the high nitrate content of the beetroot. The study correlated high nitrate concentrations in the blood following ingestion of the beetroot juice and the drop in blood pressure. Dietary nitrate, such as that found in the beetroot, is thought to be a source for the biological messenger nitric oxide, which is used by the endothelium to signal smooth muscle, triggering it to relax. This induces vasodilation and increased blood flow.
Other studies have found the positive effects beetroot juice can have on human exercise and performances. In studies conducted by the Exeter University, scientists found cyclists who drank a half-litre of beetroot juice several hours before setting off were able to ride up to 20 per cent longer than those who drank a placebo blackcurrant juice.
This study follows research by Barts and the London School of Medicine and the Peninsula Medical School (published in February 2008 in the American Heart Association journal Hypertension), which found that beetroot juice reduces blood pressure.
Adapted from materials provided by University of Exeter.