"Some people like to exercise more than others do, but why this is so is not well understood," lead author Sachiko Haga-Yamanaka of UC Riverside said in a news release. "Taken together, our results show vomeronasal receptors as trait locations for voluntary exercise behavior in mice."

"It's not inconceivable that someday we might be able to isolate the chemicals [i.e., smells] and use them like air fresheners in gyms to make people even more motivated to exercise," senior author Theodore Garland added.

— Read more in Need Motivation to Exercise? Olfaction Is a Primal Motivator at Psychology Today.