How does beetroot affect human stamina and muscles?

The study behind this claim set out to test the theory that beetroot juice, a rich source of nitrates, can increase muscle stamina. It found that seven volunteers who drank half a litre of beetroot juice each day for a week doubled the amount of nitrate in their blood. When tested on an exercise bike, the rate at which their muscles used up energy and oxygen was found to be slowed.

Problematically, because of its small size and the short-term physiological measurements that were taken, this study is not strong evidence that beetroot juice can increase stamina. More research is needed.


Where did the story come from?

The study was carried out by researchers from the School of Sport and Health Sciences at the University of Exeter, and the Peninsula Medical School. No sources of funding are reported.
The study was published in draft in the peer-reviewed Journal of Applied Physiology.


What kind of research was this?

The purpose of this study was to investigate further how a short-term diet of nitrate might result in muscles using less oxygen during exercise. The researchers had looked at this effect in previous studies and noted that people fed these diets seemed to have an improved tolerance of high-intensity exercise.

The researchers set up the study as a randomised controlled trial, an appropriate design for testing this sort of theory. The researchers used concentrations and volumes of chemicals designed to maximise the effect of nitrate on muscles. No side effects were reported except for the red colouration of urine. Whether or not beetroot juice can be used as a natural nitrate supplement, and whether it is of benefit to athletes needs further testing.


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