Effects of interval training versus continuous training on coronary artery disease: an updated meta-analysis of randomized controlled trials.

Objective: Exercise training-based cardiac rehabilitation is a safe intervention to improve aerobic exercise capacity, metabolic parameters, muscle strength, quality of life, and survival in patients with coronary artery disease (CAD). This study aimed to evaluate the effects of interval training (IT) and continuous training (CT) on CAD for appropriate treatment. Methods: We retrieved 12 high-quality randomized controlled trials (RCTs) till August 13, 2019, focused on the effects of IT and CT on patients with CAD from the Pubmed, Embase, and Cochrane Library databases. The following disease-related parameters were collected: peak oxygen uptake (peak VO2), peak heart rate (HR), respiratory exchange ratio (RER) at the peak VO2, heart rate recovery, resting HR, resting systolic blood pressure (SBP), and resting diastolic blood pressure. Additionally, study quality was assessed using the Cochrane risk assessment tool, and heterogeneity was estimated using I2-statistic and Q-test. The effect size was presented with weighted mean difference (WMD) and 95% confidence intervals (CIs). Results: No publication bias was identified in the selected 12 RCTs. The pooled data showed a significant increase in the peak VO2 (WMD = -2.00, P < .0001), peak HR (WMD = -5.88, P = .0003), and RER at the peak VO2 (WMD = -0.02, P = .0001) in the IT group compared to the CT group. SBP (WMD = -3.23, P = .0498) showed significant improvement in the IT group compared to the CT group. Conclusions: IT helps improve cardiorespiratory fitness in patients with CAD because it brings about greater improvement in the peak exercise capacity and resting SBP compared to CT.