Forget punishing gym workouts and jogging miles uphill.
The key to boosting stamina could be as simple as a glass of beetroot juice. A daily dose apparently allows us to exercise for longer before tiring. Just under a pint of beetroot juice a day also lowers blood pressure, boosting heart health.
With some of the benefits even surpassing those gained from the strict training routines followed by professional sportsmen, the researchers admit to being stunned by the results.
And they say that while the earthy tang of the juice might not be to everyone's taste, it could have a big impact on everyone from athletes training for big events to pensioners who lack the energy to walk to the shops.
The researchers, from the University of Exeter and the Peninsula Medical School, in the same city, recruited eight healthy young men to complete a series of cycling tests. They took them twice - after drinking beetroot juice once a day for six days and after drinking blackcurrant cordial.
When tasked with cycling at an easy pace, the men used less oxygen after drinking beetroot juice, the Journal of Applied Physiology reports.
This indicates that their muscles were able to do the same amount of work while spending less energy. When they were asked to cycle for as long as they could before stopping, the beetroot juice allowed them to pedal an extra minute-and-a-half before running out of energy.