Abstract
INTRODUCTION: Guidelines widely recommend exercise training as a complementary therapy for individuals with heart failure. While research highlights the potential of both high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), a systematic review is required to solidify their effects on improving patients' oxygen uptake, functional capacity, cardiac function and quality of life (QoL). OBJECTIVE: This meta-analysis aimed to compare the efficacy of HIIT and MICT on cardiopulmonary fitness, functional capacity, cardiac function and QoL among individuals with heart failure. METHOD: This review adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in International Prospective Register of Systematic Reviews (PROSPERO; CRD42024602309). We searched PubMed, Cochrane Controlled Register of Trials (CENTRAL), Scopus, Web of Science, ProQuest, Embase, Google Scholar, PubMed Central (PMC), Elton B. Stephens Company (EBSCO) and Wiley. Risk of bias was assessed with the Revised Cochrane for Risk-Of-Bias Tool for Randomized Trials (RoB 2), and analyses were conducted in RStudio version 4.4.1. (Posit PBC, Massachusetts, USA) using the 'meta' package. RESULT: A total of 21 randomized controlled trials were included in the analysis. The overall quality assessment showed a low risk of bias. We found that the HIIT group is favourable in terms of cardiac function improvement, represented by left ventricular ejection fraction (LVEF; mean difference [MD]=2.69 [95% confidence interval (CI): 0.01, 5.38; p=0.0495]), peak oxygen uptake (peak VO(2); MD=1.19 [95% CI: 0.43, 1.95; p=0.0021]) and functional capacity, assessed with the six-minute walk test (6MWT; MD=24.87 [95% CI: 11.19, 37.75; p=0.0002]). Furthermore, HIIT showed non-significant trends towards improvement in QoL (MD=1.11 [95% CI: -1.02, 3.24; p=0.31]) and oxygen pulse (MD=1.03 [95% CI: -0.18, 2.24; p=0.095]). CONCLUSION: HIIT appears to be more effective than MICT in improving functional capacity, such as LVEF, peak VO(2) and 6MWT, as well as cardiac functional outcome.