We all know the adage saying that smile is contagious. The innocent smile of a kid or the cheeky one from the beautiful stranger you see every day in your tram are ways to put you in a good mood. But, what about scent?

As you may know, scent is linked to emotion as the olfactory bulb is part of the brain’s limbic system.

A study made by European searchers has found that it might be possible to subconsciously trigger a state of happiness using the scent of sweat. Ok, it may seem odd a first, as to follow the tram example, an odour of sweat is more likely to make you hate public transports. Furthermore, we are talking here of sweat slightly produced by someone who is happy himself, not who run a marathon and forget to shower for three days after this.

The experiments also suggest that we not only breathe in the upbeat emotions of others, but by doing so we actually become happier ourselves.

“Human sweat produced when a person is happy induces a state similar to happiness in somebody who inhales this odor,” said study co-author Gun Semin, a research professor in the department of psychology at Koc University in Istanbul, Turkey, and the Instituto Superior de Psicologia Aplicada in Lisbon, Portugal.

To see whether the same holds true for the happier feelings, Semin’s team gathered sweat samples from 12 young men after each watched videos designed to induce a variety of emotions, including happiness.

In turn, 36 equally healthy young women were engaged to smell the samples while their reactions were monitored. The smell group, explained investigators, was confined to women because women typically have a better sense of smell than men and are also more sensitive to emotional signalling.

The faces of women who smelled “happy sweat” displayed facial muscle activity deemed to be representative of happiness.

Andreas Keller, a research associate with The Rockefeller University in New York City, said the study findings make intuitive sense.

“Hearing happy people and seeing happy people makes you happier,” he said, “so the fact that smelling them would make you happier, too, is probably not so surprising.”