A new study has found that athletes can increase their endurance in intense exercise by 16 per cent – just by drinking a simple glass of beetroot juice.

Dramatic improvements in sports performance are usually eyed with suspicion, but recent research from a team of scientists in Exeter, UK, has found one performance enhancer that may give athletes a winning boost and get them through drug tests without breaking a sweat: Beetroot juice.

Recently published in the Journal of Applied Physiology, the study reports that the eight healthy male test subjects, aged 19 to 38, were given 500ml of organic beetroot juice to sip each day for six consecutive days. On days four, five and six they were asked to complete both fixed-rate moderate-intensity and fixed-rate severe-intensity cycling activities. On a separate six-day period, they were given a placebo blackcurrant cordial drink, and asked to complete the same tests. Compared to the placebo group, the beetroot group not only performed better, but they also had lower systolic blood pressure.

"After drinking the beetroot juice, test subjects needed 90 per cent less oxygen than they did on the placebo."

The research project was inspired by another study run by a Swedish team of scientists, which found that taking pharmacological sodium nitrate over six days reduced oxygen cost during moderate exercise. From this the Exeter scientists wanted to see if the same results could be achieved with a more natural form of nitrate. So, thanks to its high nitrate content and its ability to be juiced, beetroot was the chosen vegetable.

By reducing the cost of oxygen during exercise, the volume of oxygen you need to breathe in, your VO2, is reduced. It consequently becomes easier to do moderate exercise, and also increases your ability to tolerate high-intensity exercise for a longer period of time. After drinking the beetroot juice, test subjects needed 90 per cent less oxygen than they did on the placebo. For the severe-intensity test, they were able to cycle for an average of 11.25 minutes while on beetroot juice – 92 seconds longer than on the placebo. This translates into a two per cent reduction of time to cycle the same distance – a pretty significant number for any serious sporting competitor stepping up to the mark.

The scientists are not really sure of the mechanisms at play, but they suspect that the boost in stamina could be a result of the nitrate turning into nitric oxide in the body, which they say reduces the cost of oxygen.

One thing is for sure: this is likely to be of interest to both professional and amateur athletes. In reference to the moderate-intensity tests, Professor Andy Jones, lead researcher from the University of Exeter’s School of Sport and Health Sciences, says they “were amazed by the effects of beetroot juice on oxygen uptake because these effects cannot be achieved by any other known means, including training.” The researchers hope that this has the potential to help many who find simple daily activities an effort because of the large amount of oxygen they need to consume just to do them, such as those with cardiovascular or respiratory problems and the elderly.

There are – at this stage – no known negative side effects to consuming beetroot juice other than a pinkish hue to your urine. Some claims in the past have been made about links with an overly nitrate-rich diet and cancer, but Professor Jones believes this is overstated. “Just eating five portions of fruit and vegetables a day (which is known to promote health and is recommended by many governments) will provide more nitrate than is recommended,” he tells TALK. “The Japanese diet contains a lot of nitrate as does the so-called Mediterranean diet and these individuals live generally longer and do not seem to suffer from any greater risk of cancer. Nevertheless, we would not recommend more than 500ml of beetroot juice per day.”  

The surprising results have spawned a whole new batch of questions for the researchers to investigate – such as, what are the specific benefits of beetroot juice for people with health problems? What is its ergogenicity (its performance-enhancing capabilities) for endurance athletes? And how long before exercise can it be consumed to have an effect? Can you, for example, slam down a bottle of beetroot juice half an hour before a run like you might with a commercial sports drink, and still expect to reap the benefits? Regardless of future research, this revelation about beetroot juice has no doubt set the hearts of health drink manufacturers racing.