Diet, Exercise Improve Exercise Capacity in Certain Heart-failure Patients
WASHINGTON, D.C. — A randomized clinical trial of 100 patients found that diet and exercise — alone or combined — improved exercise capacity in obese older patients with a particular type of heart failure.
The trial is the first to show that this dietary intervention was effective in improving exercise capacity and reducing symptoms in patients with heart failure with preserved ejection fraction (HFPEF). The results appeared in the Jan. 6 issue of the Journal of the American Medical Association. The study was supported primarily by the National Institute on Aging.
HFPEF is the most rapidly increasing form of heart failure, especially in older adults. It occurs primarily in overweight and obese older women and is associated with high rates of morbidity, mortality, and healthcare expenditures. Exercise intolerance — fatigue and shortness of breath with exertion — in HFPEF patients was recently shown to be associated with increased body weight.
Dr. Dalane Kitzman and colleagues at Wake Forest University School of Medicine randomized trial participants to four groups: diet alone, exercise alone, diet and exercise together, or control. After 20 weeks, people in the three intervention groups showed improved exercise tolerance, measured by peak exercise oxygen consumption. The diet and exercise groups both showed improvement; however, the combination group had almost twice the improvement in oxygen consumption. In addition to improving exercise capacity, diet and exercise decreased the amount of fat cells within the leg muscle, the researchers found. Fat, which infiltrates leg muscle, contributes to reduced exercise capacity in heart failure.
This is the first randomized controlled trial of calorie restriction in this patient population. While the researchers noted that follow-up studies are needed to investigate the loss of muscle mass associated with weight loss, this research supports a treatment for heart failure that relies on diet and exercise, unlike previous treatments which focused on regulating heart function through medication.