Researchers at Duke University Medical Center asked more than 2,800 people hospitalized with obstructive coronary artery disease about their expectations for recovering and returning to a normal life. Those who had a positive attitude about the future were less likely to die over the subsequent 15 years, according to the study published online Monday in the Archives of Internal Medicine.

How positive thinking helps recovery — if in fact it does — remains a bit of a mystery. The study offers these possibilities:

“Optimists have been found to be more likely to address the demands of a problem rather than withdrawing or focusing on its emotional consequences. This coping predisposition may generalize to those patients with high recovery expectations, making their coping more effective in reducing risk factor levels and improving levels of life satisfaction.

“A second hypothesis is based on the likelihood that those with pessimistic expectations will experience more tension and negative emotions during the recovery period, resulting in heightened stress reactions, autonomic dysregulation and other physiological responses that increase the risk of cardiac events.”

All this isn’t to say that you can simply wish away the ill effects of coronary disease. But by all means, nurture positive thoughts — along with staying on a healthy path.