Researchers have found that the old aphorism 'Grin and bear it' actually may have its roots in science and medicine. A new study found that, for people under stress, smiling helped them cope with stress, even if they were not actually happy.

Three facial expressions were studied: a neutral unsmiling expression, standard smiles which use just the muscles surrounding the mouth, and Duchenne smiles, or smiles that use the muscles surrounding the eyes and mouth. (You can see the difference between such smiles here.) Previous research has confirmed that emotions can have an impact on stress, and that smiling can help alleviate stress; the research by psychologists Tara Kraft and Sarah Pressman from the University of Kansas, however, is the first of its kind to measure the manipulation of smiles.

Kraft and Pressman instructed 169 participants in their trial to use chopsticks in their mouths in such a way as to affect facial expressions. The chopsticks were essential to the experiment because they allowed participants to smile without being aware that they were doing so.

Next, participants were tasked with fulfilling some multitasking activities that had been designed to be stressful. The first task asked participants to trace a star with their non-dominant hand in a mirror while looking at a picture of a star. The other task involved participants submerging their hand in an ice-cold pool of water. Researchers measured their stress levels with their heart rates and by asking participants questions about how stressed they were.

The psychologists concluded that, during brief bouts of stress, the effects of it could be alleviated through smiling. The effects were particularly pronounced with Duchenne smiles, but in either case, the positive effect of smiling could be felt whether or not the participant actually felt happy.

Researchers conclude that, the next time you are in a stressful situation like a traffic jam that might cause you to be late to a meeting, smiling may ease your stress.

The study will be published in an upcoming issue of Psychological Science journal.