Impact of exercise training at different intensity levels on cardiac function and exercise capacity in patients with chronic heart failure: a prospective cohort study

Objective: To investigate training at different inten-sity levels on cardiac function, exercise capacity, and health-related quality of life in patients with chronic heart failure. Methods: This prospective cohort study enrolled patients with chronic heart failure at Beijing Reha-bilitation Hospital, Beijing, China from January 2018 to January 2020. Participants received conventional therapy (non-exercise group) or therapy plus cycle ergometer exercises at an intensity of 80% anaerobic threshold (EA group) and Delta 50% power above anae-robic threshold (EB group) for 12 weeks. The primary outcome was peak oxygen uptake. Results: Forty-five patients (15/group) completed the study without serious complications. Exercise training at an intensity of Delta 50% power above anae-robic threshold had better effects on exercise capa-city than exercise at an intensity of 80% anaerobic threshold, as shown by a greater improvement in peak oxygen uptake (20.3 +/- 4.1 vs 16.8 +/- 3.2 mL/ min/kg), peak O2 pulse (12.5 +/- 2.3 vs 10.1 +/- 2.1 mL/beat), and peak workload (123.1 +/- 26.9 vs 102.8 +/- 29.5 W) in patients with chronic heart fai-lure (all p < 0.001). Exercise improved the 6-min walk test distance (control: 394.0 +/- 74.1; EA: 481.4 +/- 89.4; EB: 508.9 +/- 92.5 m; p< 0.001) and health-related quality of life (control: 40.7 +/- 12.3; EA: 16.2 +/- 8.6; EB: 11.5 +/- 6.4; p< 0.001). Conclusion: Compared with an intensity of 80% anaerobic threshold, exercise training at an inten-sity of Delta 50% power above anaerobic threshold was safe and had better effects on cardiac function, exercise capacity, and health-related quality of life.