More Effective Exercise Modalities in Older Congestive Heart Failure Patients

BACKGROUND:

The amount of functional skeletal muscle that CHF patients are able to preserve is a major independent predictor of their ability to maintain physical function. Older patients with CHF (who make up the vast majority of CHF patients) are least able to do this. The disease is marked by a loss of aerobic muscle fibers, while aging is marked by a loss of glycolytic muscle fibers. Because the disease may be physiologically different in older CHF patients than in younger ones (due to loss of both muscle types in older CHF patients), they need different therapeutic approaches. Strategy tests aimed at increasing muscle mass through resistance strength training in systolic failure patients have been rare, small, and generally lacking older participants. The studies done among younger CHF patients have shown that both aerobic, and combination aerobic and strength training can increase work capacity, oxidative muscle activity, and glycolytic muscle strength. Additionally, combination training can improve cardiac measures, including LVEF.

DESIGN NARRATIVE:

An estimated 200 participants age 65 and older with Class II and III CHF and LVEF 20% to 40% will be included in this study. Their work capacity will be measured in watts on a cycle ergometer exercise stress test (Time 1). They will be randomized by gender, race, and disease severity into two exercise groups: 1) resistance and aerobic training (RA); and 2) aerobic training (A). Both groups will exercise three times a week for 4 months. At the end of the 4 months of training, the cycle ergometer stress test will be repeated (Time 2). By comparing changes in maximum watts achieved from Time 1 to Time 2 in each group, an assessment can be made of the effectiveness of each exercise program in improving work capacity. Secondarily, measures will be performed and compared of myocardial remodeling, leg strength, and leg muscle oxidative capacity at Time 1 and Time 2. The goal of the study is to determine the following:

1. If low resistance frequent repetition resistance training combined with aerobic training increases aerobic work capacity more than pure aerobic training.
2. If any improvement in aerobic work capacity is due to changes in muscle fiber composition, local blood flow, arterial endothelial function, or some combination.