Beetroot juice could help us exercise for longer, new research suggests.
The study found the drink enhanced people's performance in exercise after they drank it for two weeks.
It reduced the workload on the heart and made the organ better able to deliver oxygen to the body's muscles.
This means people can work out for longer before their muscles become fatigued, researchers said.
People who drank the bright red juice also had lower blood pressure, a finding which backs up previous research on this topic.
Beetroot juice is found in most health food shops and usually costs around £2 a bottle.
Researchers said the benefits of the drink come from the fact it contains the molecule nitrate.
When converted in the body, nitrate can dilate the blood vessels and increase blood flow, both important factors for exercise performance.
Nitrate also triggers a series of chemical reactions in the blood, which can increase oxygen in areas of the body which are specifically lacking supply.
As well as beetroot, high concentrations of nitrate are also found in celery, cabbage and other leafy green vegetables such as spinach and some lettuce.
As part of the study, men who drank beetroot juice for 14 days had lower blood pressure and more dilated blood vessels when they were exercising and when they were resting.
Blood vessels also dilated more easily and the heart consumed less oxygen when they were working out.
Writing in the journal American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, the researchers said: ‘Exercise can be performed at a given workload for a longer period of time before the onset of fatigue.’
The study comes after a slew of research has revealed how beetroot juice has heart-related benefits.
Another paper, published in the journal Hypertension, found drinking one cup of beetroot juice a day led to a seven per cent drop in blood pressure readings in people with high blood pressure.
And before that, a study published in the Journal of Applied Physiology, found men who drank 500ml of beetroot juice a day were able to cycle 16 per cent longer on an exercise bike before tiring out.