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 intensity 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 Rehabilitation 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 Δ50% power above anaerobic 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 Δ50% power above anaerobic threshold had better effects on exercise capacity 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 failure (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 intensity of Δ 50% power above anaerobic threshold was safe and had better effects on cardiac function, exercise capacity, and health-related quality of life. LAY ABSTRACTThe aim of this study was to investigate training at different intensity levels on cardiac function, exercise capacity, and health-related quality of life in patients with chronic heart failure. Exercise training at an intensity of Δ 50% power above anaerobic threshold (mild anaerobic exercise) had better effects on exercise capacity than non-exercise and intensity of 80% anaerobic threshold (aerobic exercise). In addition, exercise resulted in improved health-related quality of life compared with non-exercise. Therefore, the benefit may be greater if the exercise intensity is increased appropriately under safe conditions.