Beyond the upside of having better race photos, smiling during a run may also make the effort seem easier according to a recent study published in the journal Psychology of Sport and Exercise.

Researchers from the Ulster University School of Psychology in Ireland and Swansea University in Wales discovered that smiling improved running economy by 2.8 percent over frowning and 2.2 percent as compared to normal thoughts and facial expressions. Based upon their studies, the scientists suggested that smiling may even decrease effort perception during exercise, while frowning may make exercise feel more difficult.

Fake smiles didn’t cut it though. Smiles had to be genuine to trigger a relaxing response. Thinking positive thoughts, seeing friends and family along a race route and smiling and waving during training runs are all ways to achieve a real smile. However, smiling for an entire run or race may be unrealistic.

“Periodic smiling during training or racing may be an effective way to relax, and to reduce sensations of effort during a run,” says Dr. Noel Brick, one of the authors of the study, told The Irish Times. “I think periodic smiling is best, maybe for 30 seconds, once or twice every mile, as longer periods of smiling may be difficult to maintain.”

Brick and his team put 24 non-professional runners through a series of treadmill running tests, including running with face masks to measure breathing, running while smiling, running while scowling and running normally. They were then asked about their various coping strategies and how they felt on their runs. While smiling didn’t make everyone’s performance improve, the final results showed almost a 3 percent overall improvement in efficiency. As runners know, every little bit helps. Plus smiles are free and generally come pretty easy when you’re enjoying a run.

For proof, just look at Deena Kastor, who believes in the power of positivity to get winning results and can often be seen beaming during races. And who knows if smiling made the final yards of Meb Keflezighi’s 2014 Boston Marathon win feel easier, but damn if watching the footage of him smiling, fist pumping the air, doesn’t make you smile and want to go out for a run!