Inactivity may be why depression is a risk factor for heart disease

Depression is a risk factor for heart disease and has also been linked to repeat heart attacks or strokes in patients recovering from these serious events. But new research suggests that it's a lack of exercise by people with depression that's to blame.

Researchers led by Dr. Mary A. Whooley at the VA Medical Center in San Francisco found that patients with symptoms of depression were 50 percent more likely to have heart failure, heart attacks, strokes, or die compared with patients without depressive symptoms. After accounting for other illnesses they had, the depressed group's risk was 31 percent higher than in non-depressed patients.

But when differences in behaviors such as smoking, drinking, and physical activity were excluded, the link between depression and cardiovascular events faded away. Physical inactivity was associated with a 44 percent higher rate of cardiovascular events.

The study in the Journal of the American Medical Association followed more than 1,000 heart patients for almost five years.

Based on this study, the authors can't say whether being physically inactive was the cause or the result of feeling depressed. But they suggest that shouldn't matter, given how many patients suffer from both depression and heart disease and how few treatments seem to help.

"These findings raise the possibility that increased exercise may decrease the risk of cardiovascular events associated with depression," they write.