Exercise And Cardiovascular Health: A Dose-response Meta-analysis For Patients With Cardiomyopathy

BACKGROUND: Cardiomyopathy is a high-risk cardiovascular disease characterized by enlargement, thickening, or stiffness of the heart muscle, which can lead to heart failure or cardiac arrest. While the American College of Sports Medicine (ACSM) guidelines recommend 150 minutes of moderate-to-vigorous physical activity (hereafter exercise) per week for the general population, less is known about the recommended exercise prescription for patients with cardiomyopathy. This meta-analysis aims to investigate the effects of exercise dose-response on patients with cardiomyopathy. METHODS: The PRISMA guidelines were followed in conducting the meta-analysis. Articles were searched in English peer-reviewed journals using the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, and Medline. The search yielded 263 potentially relevant papers. RESULTS: The meta-analysis identified 11 experimental studies that ranged from 8 to 26 weeks in length. Effect sizes were adjusted based on the study sample. Across these studies, the outcome of interest varied and not all outcomes were reported in all studies. Specifically, we found that VO2 Max (8 studies), resting heart rate (6 studies), and ejection fraction (7 studies) were commonly reported. On average, exercise interventions had a positive effect on all outcomes increasing both VO2 Max (d = 1.08), ejection fraction (d = 0.6), and reducing resting heart rate (d = -0.39). Of those studies, three prescribed less than the recommended dosage of 150 minutes per week of exercise, with the remaining eight studies reporting 180 to 246 minutes of exercise per week. However, a 24-week intervention with the largest sample (n = 73 participants) administered only 100 minutes per week of exercise reported some of the strongest effects across all outcomes (VO2: d = 1.01; resting heart rate: d = -0.87; ejection fraction: d = 0.85). CONCLUSION: Studies reporting adherence to or achieving more than the ACSM guidelines have found clinically meaningful effect sizes across key cardiovascular parameters. However, evidence also supports that longer adherence to an exercise program that is lower than the ACSM guidelines, can yield beneficial health outcomes.