We all know smiling is a good idea. It brightens up our own and others’ day. And if we have to get wrinkles eventually, smile-wrinkles are much better than frown wrinkles, wouldn’t you say?

But scientists now think that smiling could drastically improve your performance in the gym.

A study was conducted at Ulster University in Northern Ireland and Swansea University in Wales to test the theory. The results were published in the September edition of Psychology of Sport and Exercise. It involved 24 experienced athletes –both men and women. Unaware of the purpose of the study, the participants each completed four six-minute sessions on a treadmill. With each set, they were asked to maintain a different facial expression – at first a genuine smile for the duration of the run, then a frown, then a completely relaxed expression and finally they were asked to run with their normal, most natural facial expression – these runs were completed on separate days.

The study produced varied results overall – but smiling during the run yielded the best results out of the four sets. Interestingly, as the six-minute runs became tougher, athletes found it harder to maintain a sincere smile, which the New York Times reports to have weakened results. According to Noel Brick, a lecturer in sport and exercise psychology at Ulster University, the answer might be to “grin sincerely near a race’s end, but in 30-second bursts, rather than continuously”.

Although this is a relatively recent discovery, smiling as a method to improve athletic performance has made it to the top levels of professional sports. Gretchen Reynolds reports that “Eliud Kipchoge, the Kenyan marathon runner, periodically grinned through the final miles of his fastest-ever marathon, which he completed in 2 hours 25 seconds; afterward, he said that he had hoped that the smiling would ease him to the finish line”.

So why not start trying it for yourself and see how your results in the gym improve?