The benefits of exercise keep mounting.
Now scientists say regular exercise is safe even for people who survive heart failure and may slightly lower their risk of death or another hospitalization.
The finding is from the largest and most comprehensive clinical trial to examine the effects of exercise in chronic heart failure patients, according to an announcement today from the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.
The study also found that heart failure patients who add regular, moderate physical activity to standard medical therapy report a higher quality of life compared to similar patients who receive medical therapy only.
"Many patients and health care providers have continued to be concerned about the safety of aerobic exercise for heart failure," said NHLBI Director Dr. Elizabeth G. Nabel. "With the results of this robust clinical trial, we can now reassure heart failure patients that, with appropriate medical supervision, regular aerobic exercise is not only safe but it can also improve their lives in really meaningful ways."
The results are published in two papers in the April 8 issue of the Journal of the American Medical Association. The study was conducted at 82 centers in the United States, Canada, and France.
About five million people in the United States have heart failure, a potentially life-threatening condition in which the heart has a reduced ability to pump blood through the body. It is leading cause of hospitalization among Americans age 65 and older.
The problem is growing, the scientists said. Each year, another 550,000 people are diagnosed for the first time.
Heart failure usually develops over several years and commonly results from coronary artery disease, high blood pressure, or diabetes. Treatment typically includes lifestyle changes, medicines, and regular outpatient follow-up with a health care provider. Some patients also need medical devices to help the heart pump better, or surgeries, such as a coronary artery bypass operation or heart transplant.
Earlier, smaller clinical trials have suggested that exercise is beneficial for heart failure patients, and clinical guidelines recommend moderate exercise for this condition. Nonetheless, safety concerns persisted.
The new study followed 2,331 patients with moderate-to-severe systolic heart failure (average age 59) for up to four years (average of 2.5 years).
About one-half of the participants were randomly assigned to receive usual care alone, which included medical and device therapy as prescribed by their physicians and educational materials on disease management. They were also asked to engage in 30 minutes of moderate physical activity on most days of the week.
The other half of the participants were in the exercise training group, and they received usual care plus 36 sessions of group-based, supervised aerobic exercise training (walking or stationary cycling) of up to 35 minutes three times per week. These participants were asked to transition to home-based training at the same intensity five times per week for the remainder of the study and received a treadmill or stationary bike for home use and a heart rate monitor.
Compared to the usual care group, the exercise training group had slightly fewer (statistically non-significant) deaths or hospitalizations from any cause.
When researchers adjusted the findings for the strongest predictors of death or hospitalization — initial exercise capacity, history of atrial fibrillation, depression, cardiac pumping function, and cause of heart failure — exercise training was linked to an 11 percent lower risk of all-cause death or hospitalization and a 15 percent lower risk of cardiovascular-related death or heart failure hospitalization.
In addition, there was no significant difference in serious adverse events between the two groups, such as an abnormal heart rhythm, hip fracture, or hospitalization related to exercise, suggesting that exercise training was well tolerated and safe, the researchers explained.
The benefits of exercise may even be underestimated by the study results because many of the usual care participants also exercised, the scientists point out.