A mouthful of sports drink may boost your performance

There are now many sugary energy drinks on the market. Are they any use? Studies show that just a mouthful of these drinks gives the brain a strong boost and improves athletes' performance.

An earlier study had suggested these drinks bring no benefit. A new study tried rinsing the mouth with three different drinks without swallowing them. Volunteers did an hour-long cycling test, and were compared with people who rinsed with water and an artificial sweetener of the same taste.

MRI scans showed activity in the brain's reward and pleasure centre, and those who rinsed with the sugary drinks finished the test 2% faster. "Most of the benefit of carbohydrate in exercise comes from the signal the brain receives directly from the mouth, not from supplying sugar to the muscles," said Dr Ed Chambers of the University of Birmingham.

According to the new study, published in the Journal of Physiology, athletes don't need to drink energy drinks to perform better: rinsing a mouthful and spitting it out activates the brain so it believes there is extra fuel. "In the end, the brain controls performance through nerve signals," Dr Chambers says.

But some ask: what happens when the brain realises the promised energy hasn't arrived? It may be best to rinse, and then drink.