Prevention : To get a clearer sense of the benefits ( and potential risks ) of exercise for heart failure patients , Flynn -- along with Christopher M. O'Connor , M.D. , director of the Heart Center at Duke , as well as colleagues from several centers across the country -- randomly assigned 2,331 men and women with heart failure to one of two groups : standard medical care plus aerobic exercise training or standard care only . Exercise in heart - failure patients is safe , increases well - being , reduces pain . About 5 million people in the United States have chronic heart failure . In heart failure , the heart is too weak to pump blood through the body effectively .
Prevention : Exercise in heart - failure patients is safe , increases well - being , reduces pain . About 5 million people in the United States have chronic heart failure . In heart failure , the heart is too weak to pump blood through the body effectively .