Reuters reports on a study in Circulation that found keeping a positive attitude may improve outcomes for ischemic heart disease patients. The study included 607 heart disease patients who were surveyed in 2005 about their mood and lifestyle, including the amount of exercise they got. The researchers then analyzed death rates in 2010. They found that patients who reported greater positive affect and greater amounts of exercise were less likely to die from ischemic heart disease. It is unknown if positive outcomes are a direct cause of positive attitude, but scientists speculate that exercise may mediate the connection.