Long-term Enrollment in Cardiac Rehabilitation Benefits Cardiorespiratory Fitness and Skeletal Muscle Strength in Men With Cardiovascular Disease

BACKGROUND: Despite known associations between fitness and recurrent cardiovascular events, changes in cardiorespiratory fitness (CRF) and muscle strength with long-term cardiac rehabilitation (CR) have not been extensively examined. The objectives of this study were to (1) examine changes in CRF and muscle strength associated with long-term CR program enrollment in men, and (2) compare these changes to previously published rates of decline (2.0% per year for CRF and 2.36% per year for muscle strength in healthy age-matched individuals). METHODS: Data were extracted from the program charts of 160 men (64 ± 9 years) who were enrolled ≥ 1 year in a maintenance-phase CR program and who completed ≥ 2 exercise tests. CRF was represented by peak oxygen consumption (VO_2peak, mL/min/kg). The skeletal muscle strength was assessed using 1-repetition maximum tests for chest press, seated row, and knee extension. Mixed model analyses with polynomial functions were used to determine changes in CRF (up to 5.5 years) and muscle strength (up to 10 years). RESULTS: CRF increased nonlinearly up to 3 years (range, 0.33%-3.23% per year) and then declined nonlinearly to the 5.5-year endpoint (range, 1.03%-2.59% per year). Chest press and seated row strength declined at < 1% per year over 10 years, whereas knee extension increased nonlinearly by 0.18%-1.40% per year from baseline until 4 years and then declined nonlinearly at 1.00%-3.58% per year until the 10-year endpoint. All declines were similar to literature rates. CONCLUSIONS: The results indicate that significant health benefits are associated with maintenance-phase CR programs for men. Enrollment was associated with preserved CRF and lower body muscle strength for 3-4 years.