Durham, N.C. — The American Heart Association has released new guidelines that point to depression as a significant risk factor for heart disease. The association also says heart disease can trigger depression.

A current Duke study called UPBEAT is finding that the best medicine for both illnesses is exercise.

Researchers compared exercise alone with taking antidepressant medication alone to see how each improved depression and cardiovascular functioning in heart patients. A control group of patients took a placebo.

Marshall Daniel, 69, was a participant in the study. He now has incorporated regular exercise as part of his lifestyle.

“I was diagnosed with clinical depression about 12 years ago, and I was on a medication for a number of years,” Daniel said.

Duke psychologist James Blumenthal said many participants like Daniel were depressed before they developed heart disease.

“So it's both a risk factor for the initial development of heart disease as well as a risk factor for people who have heart disease,” Blumenthal said.

Depression raises the risk of a cardiovascular event, like a heart attack.

Daniel said medication for depression helped him before, but there were side effects.

Before he joined the study, his symptoms of depression had returned.

“This time, I didn't take any drugs. I did the exercise and I feel much better than I did before. Not only that, but I'm getting benefit, physical benefits, from it,” Daniel said.

Researchers said regular exercise may offer a double benefit for treating depression and helping to prevent heart disease.

“Recognizing depression and treating it is very, very important for physicians,” Blumenthal said.

The Duke UPBEAT study is still enrolling participants for the 16-week program.