Earphones in the gym are as common as ears; everyone’s got a pair. And there is good reason why so many people listen to music during a sweaty workout. It makes hard work fun.

Turns out that a snappy song may actually tune our brains into a positive state of mind.

A recent study by scientists in Great Britain using mobile brain-scanning technology indicates exercise increases beta waves in the front-central region of the cerebral cortex, a wave pattern eliciting a more positive emotional state.

It’s no surprise, of course, that music produces emotion. A song on the jukebox during a first date with an eventual soulmate is forever stamped on the mind. Music can be fun and sad and uplifting.

But how our brains react listening to music while exercising has been under-studied, according to the paper published in the journal of Psychology of Sport and Exercise.

Researchers asked participants to walk 400 meters outfitted with devices attached to their scalps to measure brain waves. Some walked at their own pace listening to a popular song. Others walked while listening to a podcast of a TED talk. Finally, a third group listened to nothing at all.

The song walkers reported a 28 percent increase in enjoyment compared with those listening to nothing. The TED talk walkers enjoyed their walk 15 percent more.

With half of all Americans failing to meet federal guidelines of at least 75 minutes of vigorous or 150 minutes of moderate-intensity aerobic activity each week, the researchers suggested an obvious solution — head to the gym with a device loaded with your favorite tunes.

Oh, the song played for song walkers in this study? “Happy” by Pharrell Williams, of course.