Smiling May Reduce Stress

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Feeling good often causes us to smile, but can smiling cause us to feel good? New research suggests it might.

"Age old adages, such as 'grin and bear it' have suggested smiling to be not only an important nonverbal indicator of happiness but also wishfully promotes smiling as a panacea for life's stressful events," researcher Tara Kraft, with the University of Kansas, said in a statement. "We wanted to examine whether these adages had scientific merit; whether smiling could have real health-relevant benefits."

For the experiment, Kraft and her research partner recruited 169 participants from a university in the Midwest. The subjects were trained to maintain one of three different facial expressions — a neutral expression, a standard smile and a more emphatic smile referred to as a Duchenne smile — by holding chopsticks in their mouths. The chopsticks forced people to smile without being aware that they were doing so, the researchers explained, and only half of the group members were actually told to smile.

Chopsticks in mouth, the participants were given stress-inducing tasks, which included submerging a hand in ice water and tracing a star with their non-dominant hand by looking at a reflection of the shape in a mirror. During the testing, researchers measured participants' heart rates and self-reported stress levels.

Participants who were instructed to smile, and especially those bearing big Duchenne smiles, had lower heart rates after the stressful tasks compared to subjects who held neutral facial expressions, the researchers said. Those who weren't explicitly told to smile, but were forced into a smiling expression with the chopsticks, also had lower heart rates, but to a smaller degree. 

The results, which will be published in the journal Psychological Science, suggest smiling can help reduce stress, despite actual mood.

"The next time you are stuck in traffic or are experiencing some other type of stress, you might try to hold your face in a smile for a moment," said Kraft's partner, Sarah Pressman.