Smile! Happiness is good for your heart.

RODALE NEWS, EMMAUS, PA—A happy mind may mean a healthy heart, according to recent research published in the European Heart Journal. Researchers found that over the course of 10 years, adults who were more positive were less likely to develop coronary heart disease than their more negative peers.

THE DETAILS: At the study's outset, 1,739 adults were assessed for coronary heart disease risk factors such as high blood pressure or high cholesterol levels. Psychologists also videotaped the study subjects while asking them detailed questions about how they reacted to stressful situations, such as being stuck in traffic or dealing with stress at home or at work. Researchers measured both verbal and nonverbal responses on a positivity/negativity scale.

After 10 years, the scientists found that people who had expressed more positive emotions during that initial interview were less likely to develop coronary heart disease than their more negative counterparts. Previous studies have also found the reverse to be true, says lead study author Karina Davidson, PhD, clinical psychologist and associate professor of medicine and psychology at Columbia University. In research done with this same group of adults, a higher number of self-reported depressive symptoms was associated with an increase in risk of early cardiac death.

WHAT IT MEANS: As this study clearly demonstrates, the mind-body connection can be very powerful. In attempting to explain what’s behind the results, Davidson says, "It may be that people who tend to be happier also tend to sleep better, smoke less, and eat better foods," all of which have been associated with improved cardiac health. "Also, we know from other experiments that if you induce happiness in people, stress hormone levels decrease," says Davidson. "It's called the relaxation response. The way this works is, when you're feeling satisfied and relaxed, your entire physiological system goes into a state of repose. It’s possible that spending more time in this restful state can protect the heart."

Read on for ways to keep your heart healthy with positivity.