The Effects of Interval Training and Continuous Training on Cardiopulmonary Fitness and Exercise Tolerance of Patients with Heart Failure—A Systematic Review and Meta-Analysis

Purpose: To investigate the effects of interval training (IT) as compared with continuous training (CT) on cardiorespiratory fitness and exercise tolerance of patients with heart failure (HF), with the aim to provide reasonable exercise prescriptions for patients with HF. Methods: Through searching electronic databases, randomized controlled studies were collected. The included studies were evaluated for methodological quality using the Cochrane risk of bias assessment tool, and statistical analyses were carried out using Review Manager 5.3 and Stata MP 15.1 software. Results: A total of seventeen randomized controlled trials (i.e., studies) with 617 patients were included. The meta-analysis showed that IT can improve a patient’s peak oxygen uptake (VO2peak) (MD = 2.08, 95% CI 1.16 to 2.99, p < 0.00001), left ventricular ejection fraction (LVEF) (MD =1.32, 95% CI 0.60 to 2.03, p = 0.0003), and 6-minute walk distance (6MWD) (MD = 25.67, 95% CI 12.87 to 38.47, p < 0.0001) as compared with CT. However, for respiratory exchange ratio (RER) (MD = 0.00, 95% CI −0.02 to 0.03, p = 0.81), CO2 ventilation equivalent slope (VE/VCO2 slope) (SMD = 0.04, 95% CI −0.23 to 0.31, p = 0.75), and resting heart rate (HRrest) (MD = 0.15, 95% CI −3.00 to 3.29, p = 0.93) there were no statistical significance. Conclusions: The evidence shows that IT is better than CT for improving the cardiorespiratory fitness and exercise tolerance of patients with HF. Moreover, an intensity of 60–80% peak heart rate of IT is the optimal choice for patients. It is hoped that, in the future, more well-designed studies would further expand the meta-analysis results.