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DURHAM, N.C. -- Heart attack patients who are depressed or without social support are more than twice as likely to die of a second heart attack if they do not exercise, according the results of a large-scale national trial led by Duke University Medical Center researchers.
The study, which followed 2,078 patients, is one of the largest to examine the potential role of exercise in forestalling future heart attacks in this high-risk group of patients, the researchers said. In contrast to past studies that concentrated on Caucasian males, the researchers said the current trial was more representative of the population as a whole, with 33.6 percent being minority, 43.5 percent being women, and 38.8 percent over the age of 65.
The researchers found that after an average two-year follow-up, 5.7 percent of those who reported regular exercised had died, compared to 12 percent of those reported not exercising. Additionally, 6.5 percent of exercisers experienced a non-fatal heart attack, compared to 10.5 percent for non-exercisers.
"Our findings demonstrate the value of exercise for those heart attack patients who are at higher risk of future cardiac events because of their depression or social isolation," said lead researcher James Blumenthal, Ph.D., Duke behavioral psychologist. The results of the study were published May 4, 2004, in the Medicine & Science in Sports & Exercise, a journal of the American College of Sports Medicine.
"Exercise was associated with lower baseline levels of depression, greater reductions in the symptoms of depression, as well as increased survival," Blumenthal continued. "We believe that exercise can be valuable in treating the physical and mental health of these high-risk heart attack patients."
While the medical community is increasingly recognizing the important role of exercise in preventing initial as well as subsequent heart attacks, no study to date has looked specifically at the impact of exercise on heart attack patients considered at a high psychosocial risk for another heart attack, said the researchers.
Most previous studies on the effect of exercise on heart disease enrolled predominantly Caucasian men and patients under at age of 65, and most of those studies did not include a non-exercising group of patients as a control, said the researchers.
In 1996, the National Institutes of Health awarded a $29.6 million grant to an eight-center consortium to investigate the promise of behavior therapy interventions in a "real-world" group of patients with heart disease who were either depressed or socially isolated. The trial was dubbed ENRICHD (Enhancing Recovery in Coronary Heart Disease Patients).
Last year, The ENRICHD investigators reported in the Journal of American Medical Association (June 18, 2003), that counseling and group therapy reduced levels of depression and social isolation in these patients, but did not lower mortality or morbidity rates of study participants. For the current study, the researchers went a step further to compare the outcomes of patients enrolled in ENRICHD who exercised and those who did not.
"Our latest findings suggest exercise can be just as beneficial for patients who are older, minority or women," Blumenthal said. "This finding is important because previous studies show that men and Caucasians are more likely to exercise than women and minorities."
Blumenthal said that being sedentary should be considered as a cardiac risk factor just like other risk factors such as smoking, improper diet or uncontrolled high blood pressure.
"While our study cannot determine whether patients in the trial were sedentary because they were depressed, or whether they became depressed because they weren't physically active, we can say that patients who are depressed and sedentary are at a much higher risk of another cardiac event," Blumenthal said. "Moreover, those patients who reported that they had exercised during the six months after their heart had almost a 50 percent reduction in risk of dying or suffering further heart complications compared to the non-exercisers."
Cardiovascular disease is the leading cause of death in the United States. An estimated 13 million Americans suffer from coronary artery disease. Each year, up to one-third of the 1.5 million Americans who suffer heart attacks will die. Not only could psychological treatment result in fewer hospitalizations and lives saved, it may help reduce the cost of treating heart patients with high-tech therapies, now estimated at $100 billion a year, Blumenthal said.
"We hope that the results of this study will heighten physicians' awareness that exercise can play an important role in the treatment of their heart attack patients," Blumenthal said. "As they write their prescriptions for statins or beta blockers, we'd also like to see them recommend an exercise program."
Blumenthal is currently leading a trial to determine whether exercise can be an effective treatment for depression in middle-aged and older adults. An earlier Duke trial demonstrated that supervised exercise was just as effective as the most commonly used anti-depression medication in improving the symptoms of depression.
The trial, called SMILE (Standard Medical Intervention and Long-term Exercise) is building upon the earlier trial by randomizing patients to supervised exercise, exercise at home, standard anti-depressant medication or placebo.
Other participating medical centers in the ENRCHD trial were the University of Alabama at Birmingham, University of Miami, Yale University/Harvard University, Washington University in St. Louis, University of Washington in Seattle, Stanford University, and Rush-Presbyterian-St. Luke's Medical Center in Chicago. The University of North Carolina at Chapel Hill served as the Coordinating Center.
Note: For more information about the SMILE Study contact Dr. Krista Barbour at 919-681-2612
Journal
Medicine & Science in Sports & Exercise