Scientists are hailing the potential of dark chocolate to give fitness fans an extra edge in their training, after new research suggested the tasty treat can help to increase both the intensity and duration of workouts.

The study, which has been published in the Journal of the International Society of Sports Nutrition discovered that dark chocolate provides similar benefits to beetroot juice, now taken regularly by elite athletes after studies showed it can improve performance.

A team led by postgraduate research student Rishikesh Kankesh Patel London's Kingston University assessed the effects of dark chocolate consumption on a group of amateur cyclists. The study found that after eating dark chocolate, the riders used less oxygen when cycling at a moderate pace and also covered more distance in a two-minute flat-out time trial.

Patel said the results opened the door for more research which could eventually lead to dark chocolate becoming a staple part of endurance athletes' diets.

"Both dark chocolate and beetroot juice are known to increase nitric oxide, which is the major mechanism we believe is behind these results," he said.

"We found that people could effectively exercise for longer after eating dark chocolate – something that's not been established before in this way."

Pate is now conducting further research into dark chocolate as part of his doctoral thesis. He is hoping to discover the optimal flavanol level in dark chocolate for boosting athletic performance.

"We want to see whether the boost in performance is a short term effect – you eat a bar and within a day it works – or whether it takes slightly longer, which is what the initial research is showing," he added.

"We are also investigating the optimal level of flavanols. Once we've found the optimal chocolate dose and duration, we'll compare its effects to those of beetroot juice, and also test the influence of combining consumption of both, as they produce an increase in nitric oxide in slightly different ways."