Smile! It’s Good for Your Heart

Feeling good makes us smile, right? Sure, although a new study suggests the reverse may also be true: Smiles might be good for our health.

In the study, to be published in an upcoming issue of Psychological Science, researchers at the University of Kansas found that the act of smiling has a positive effect on our happiness and physical health, helping the heart recover more quickly after stressful events.

The researchers randomly assigned nearly 170 American college students into one of three groups. All the students were asked to mimic a research assistant who was holding chopsticks between their teeth, as were the students. (As a cover, the students were told they were participating in a multi-tasking experiment.)

In one group, the research assistant had the students unwittingly activate the facial muscles for a genuine (or “Duchenne”) smile, which involves muscles at the corners of the lips and muscles around the eyes, producing “crow’s feet” to the sides of the eyes.

In the other groups, the students were made to imitate either a “standard,” non-genuine smile—involving just the muscles around the lips, not the eyes—or no expression at all.

Next, while keeping their chopsticks and facial expressions intact, the students completed stressful tasks, including one that required participants to trace a star with their non-dominant hand over and over without going outside the box (when they drew outside the lines, they heard a loud buzzing sound). The researchers monitored the students’ heart rates before, during, and after these tasks and also asked the students how good they felt before and after performing the stressful tasks.

After the students’ heart rates spiked during the stressful tasks, the hearts of the smilers more quickly dropped back down to more relaxed rates than those of the non-smilers. What’s more, the genuine smilers showed the lowest heart rates of all. The researchers note that people whose hearts recover from stress like this are generally healthier down the line.

Similarly, all groups reported decreases in happiness following the stress, but those who smiled reported a smaller drop in happiness than those who kept a straight face.

“The smilers were protected a bit,” says Tara Kraft, the lead author of the study and a psychology graduate student at the University of Kansas.

So do the results mean we should “fake it til we make it”?

Prior research has suggested that faking a smile may actually be bad for your happiness, but in this study participants’ facial muscles moved in the exact same way as if they were naturally induced to flash a genuine smile—a crucial difference from the usual fake smile. Still, students who were explicitly told that the chopsticks were making them “smile” reported lower happiness than students who were unaware they were smiling, suggesting that consciously faking a smile may come at a cost.

In addition to providing evidence that genuine smiles are more effective for reducing stress than fake smiles, the study also suggests that smiling during a taxing task—not just after—can help the body and mind recover more quickly. Previous studies have explored only how smiling affects a person after an event, says Kraft.

“The neat thing about this is that smiling during the stressful period also has positive benefits for your heart health for several minutes after you’re smiling, which is pretty cool,” she says. “We’ve seen so much work out there showing it’s good for emotional and social health and well-being, but this really is the first study among its kind to show that smiling is beneficial to you physically.”