A new theory has triathletes seeing red, but you’ll need a strong stomach to test it out…

There have been recent reports in the press highlighting research into the effects of beetroot juice on endurance performance. Could this help you become a faster triathlete?

The test

A recent research paper (Bailey et al. 2009) investigated the effects of beetroot juice on performance. They took eight recreationally active males and, in a double blind placebo-controlled crossover study, were asked to drink 0.5L of beetroot or blackcurrant juice every day for six days. They were asked to refrain from foods high in nitrates during this time. At the end of the six days the participants were asked to perform a ride to exhaustion at an intensity that was termed ‘the severe intensity domain’.

The result

The beetroot-drinking participants were able to exercise for 11 minutes 25 seconds, which was 92 seconds longer than those who’d drank blackcurrant juice. They also investigated some of the reasons for this potential improvement. They found that when the subjects exercised at a moderate intensity, the amount of oxygen they used was decreased by 19% with beetroot juice. This is quite a remarkable finding, as it’s something that is very hard to change, even with training.

Triathlon Nutrition - BeetrootHow it works

The suggested reason for the increased ‘time to fatigue and decrease in oxygen use’ is an increase in the nitrate content of the diet, from beetroot juice. You can use the nitrate ingested from the beetroot to synthesise nitric oxide in the body. Nitric oxide plays a number of key roles within the body, in particular allowing the blood capillaries to open up and increase blood flow through the muscle. It is also important in making the muscle more efficient at using oxygen.

As with all research, there are some possible confounding factors in the study. For one, there is no measurement of the normal nitrate intake of participants. This is important because they were all asked to refrain from eating high nitrate foods. So the research could actually be showing that removing nitrates from the diet decreases performance rather than the other way around. Without a control or baseline trial it is difficult to prove that this is not the case.

Your performance

It’s difficult to say that taking beetroot juice will lead to an improvement in triathlon performance. The test used in the study was conducted at an intensity far higher than even a sprint triathlon. In theory, using less oxygen at a moderate intensity might prove to be useful for triathletes, but it’s too soon to say for sure.


The research highlights the general importance of eating foods high in nitrates. As usual, you can find these by eating a well balanced diet with plenty of fruit and vegetables, and making a few informed food choices, such as looking for foods with high nitrate content. However, at the moment it is unclear whether supplementing your diet with beetroot juice will improve your triathlon performances – so don’t give up the training just yet!