Effect of high-intensity interval training versus moderate intensity continuous training in heart failure patients on cardiorespiratory fitness and quality of life: a systematic review and meta-analysis

Introduction Heart failure is a major global health problem. High-intensity interval training (HIIT) is a form of aerobic exercise that involves repeated bouts of high-intensity effort interspersed with recovery periods. Previous meta-analyses have shown that HIIT has superior effects compared to moderate intensity continuous training (MICT) in terms of VO2peak improvements; however, discussions now focus on how exercise protocols may contribute to this superiority. Therefore, the aim of this study perform a systematic review of the eeffects of HIIT versus MICT on cardiorrespiratory fitness and health related quality of life (HRQoL) in individuals with heart failure. Methods We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. We performed a comprehensive search in the following databases: PubMed, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials and PEDro up to April 2025. Results 18 studies were included in this systematic review. HIIT improved VO2 peak by 1.49 mL/kg/min (95% confidence interval [CI]: 0.74 to 2.24; I 2 = 61.2%; N = 682) compared to the MICT group. However, our subanalysis of isocaloric exercise protocols according to the left ventricular ejection fraction (LVEF) showed no statistical significance between HIIT and MICT exercise training groups. No statistical difference was observed between HIIT and MICT for HRQoL. Conclusion This systematic review demonstrates that HIIT is superior to MICT in an overall context of HFrEF and HFpEF collectively. However, when comparing HIIT and MICT under isocaloric conditions, and considering LVEF, the superiority of HIIT over MICT in improving VO 2 peak disappears.