Changes in exercise capacity following cardiac rehabilitation in patients stratified according to age and gender. Results of the Massachusetts Association of Cardiovascular and Pulmonary Rehabilitation Multicenter Database

Abstract

Background: Using information collected prospectively from a multicenter cardiac rehabilitation database, this study was designed to evaluate baseline exercise tolerance and subsequent change in functional capacity among consecutive patients enrolled in supervised cardiac rehabilitation stratified according to age and gender. In addition, the study evaluated change in functional capacity among those with the lowest initial exercise tolerance (<5 METS) and assessed patient factors that correlate to the highest relative improvements in functional capacity after training.

Methods: A total of 778 patients performed an initial exercise test upon entry into cardiac rehabilitation, during which peak heart rate, blood pressure, and estimated peak MET levels were derived, and ischemic responses were evaluated. After 10 +/- 2 weeks of supervised prescribed exercise, 500 patients who completed the program performed follow-up exercise testing.

Results: The subjects included 558 men (72%) and 220 women (28%) of whom 492 (63%) were <65 years, 241 (31%) were 65 to 75 years, and 45 (6%) were >75 years. At baseline, the peak initial MET level for men was 8.6 +/- 3.4 METS and for women was 6.0 +/- 2.6 METs. The peak initial MET level declined with age: age <65 = 8.9 +/- 3.4 METS; age 65 to 75 = 6.6 +/- 2.6 METS; and age >75 = 5.7 +/- 2.9 METS. When stratified according to age and gender, the baseline exercise tolerance for men significantly (P <.0001) declined with age and was higher than that of women <65 and 65 to 75 years of age. After training, the relative improvement in exercise tolerance for each age and/or gender subgroup was: age <65: men 36%, women 41%; age 65 to 75: men 36%, women 50%; and age >75: men 36%, women 32%. Among 163 patients with an initial peak MET level <5, exercise tolerance rose from 4.1 +/- 0.7 to 8.3 +/- 3.5 METS (P <.0001). Multivariate analysis demonstrated that the greatest change in exercise tolerance with training was associated with those compliant patients with initial peak METS <5. No significant net change in the occurrence of exercise-induced ischemia was observed.

Conclusions: Among consecutive patients enrolled in cardiac rehabilitation, baseline exercise tolerance differs relative to age and gender, with male gender and younger age demonstrating the highest functional capacity. Exercise training yielded significant improvements in exercise tolerance among men and women of every age group including those older than 75 years, and particularly among those with an initial peak MET level <5. Thus, referral to cardiac rehabilitation programs should be advocated for both men and women, and should not be limited by age.