London ? You’ve heard it before: To avoid a heart attack don’t smoke, eat right and exercise. But it also may help to be happy, a new study says.

Researchers at Columbia University rated the happiness levels of more than 1,700 adults in Canada with no heart problems in 1995.

After a decade, they examined the 145 people who developed a heart problem and found happier people were less likely to have had one.

“If you aren’t naturally a happy person, just try acting like one,” said Dr. Karina Davidson of Columbia University Medical Center, the paper’s lead author. “It could help your heart.”

Davidson and colleagues used a five-point scale to measure people’s happiness. They then statistically adjusted to account for things like age, gender, and smoking.

For every point on the happiness scale, people were 22 percent less likely to have a heart problem. The study was paid for by the U.S. National Institutes of Health and others.

Davidson said happy people were more likely to have a healthier lifestyle.

It could also be there is an unknown genetic trait that predisposes people to be happy and to have less heart disease.

And stress often releases hormones that can damage heart muscle, researchers said.