High-intensity interval training versus moderate-intensity continuous training in patients with heart failure: a systematic review and meta-analysis.

The effects of high-intensity interval training (HIIT) in patients with heart failure (HF) remain controversial. This systematic review and meta-analysis aimed to examine the efficacy of HIIT versus moderate-intensity continuous aerobic training (MCT) on exercise tolerance in patients with HF. We searched for studies published up to 4 March 2022 in Embase, MEDLINE, PubMed, and the Cochrane Library with no limitations on data, language, or publication status. We included randomized controlled trials comparing the efficacy of HIIT and MCT on peak oxygen uptake (VO 2 ), as a measure of exercise tolerance. We pooled the data on peak VO 2 , compared HIIT to MCT, and conducted a sub-analysis if there was heterogeneity in the result. We identified 15 randomized controlled trials with 557 patients. Our meta-analysis showed that participants who underwent HIIT achieved a significantly higher peak VO 2 than those who underwent MCT (mean difference 1.46 ml/kg/min, 95% confidence interval 0.39 to 2.53; participants = 557; studies = 15; I 2  = 65.7%; very low-quality evidence). The meta-regression analysis, conducted as a sub-analysis to explore possible causes of heterogeneity, revealed that the difference in peak VO 2 between HIIT and MCT was inversely associated with body mass index (r =  - 0.508, p = 0.028, 95% confidence interval - 0.95 to - 0.07). Our systematic review showed that HIIT achieved a higher peak VO 2 than MCT in patients with HF. In addition, HIIT may be more effective in improving exercise tolerance in patients with low body mass index.