Exercise Mode in Heart Failure: A Systematic Review and Meta-Analysis

Background Optimising exercise prescription in heart failure (HF) with a preserved (HFpEF) or reduced (HFrEF) ejection fraction is clinically important. As such, the aim of this meta-analysis was to compare traditional moderate intensity training (MIT) against combined aerobic and resistance training (CT) and high-intensity interval training (HIIT) for improving aerobic capacity (VO 2 ), as well as other clinically relevant parameters. Methods A comprehensive systematic search was performed to identify randomised controlled trials published between 1990 and May 2021. Research trials reporting the effects of MIT against CT or HIIT on peak VO 2 in HFpEF or HFrEF were considered. Left-ventricular ejection fraction (LVEF) and various markers of diastolic function were also analysed. Results Seventeen studies were included in the final analysis, 4 of which compared MIT against CT and 13 compared MIT against HIIT. There were no significant differences between MIT and CT for peak VO 2 (weighted mean difference [WMD]: 0.521 ml min −1 kg −1 , [95% CI] = − 0.7 to 1.8, P fixed = 0.412) or LVEF (WMD: − 1.129%, [95% CI] = − 3.8 to 1.5, P fixed = 0.408). However, HIIT was significantly more effective than MIT at improving peak VO 2 (WMD: 1.62 ml min −1 kg −1 , [95% CI] = 0.6–2.6, P random = 0.002) and LVEF (WMD: 3.24%, [95% CI] = 1.7–4.8, P random < 0.001) in HF patients. When dichotomized by HF phenotype, HIIT remained significantly more effective than MIT in all analyses except for peak VO 2 in HFpEF. Conclusions HIIT is significantly more effective than MIT for improving peak VO 2 and LVEF in HF patients. With the exception of peak VO 2 in HFpEF, these findings remain consistent in both phenotypes. Separately, there is no difference in peak VO 2 and LVEF change following MIT or CT, suggesting that the addition of resistance exercise does not inhibit aerobic adaptations in HF. Graphical Abstract