High intensity interval training was superior to moderate intensity continuous training in improving peak oxygen consumption (WMD 1.68; 95% CI 0.81-2.55), but this benefit was lost with longer total exercise time.
Meta-Analysis (n=661)
Does high intensity interval training improve peak oxygen consumption compared to moderate intensity continuous training in patients with heart failure?
HIIT is superior to MICT for improving Peak VO2 in heart failure patients during short to medium total exercise times, but this benefit is lost with longer exercise durations, possibly due to poor adherence.
Mean Difference: 1.68 (95% CI 0.81–2.55)
INTRODUCTION AND AIMS: High intensity interval training (HIIT) is considered as an alternative exercise modality to moderate intensity continuous training (MICT) for heart failure (HF) patients. Yet a growing number of trials demonstrated inconsistent findings about the effectiveness of HIIT versus MICT until SMARTEX study and OptimEx-Clin study have made a consistent negative conclusion that HIIT was not superior to MICT. The aim of this study was to conduct a meta-analysis involving a subgroup analysis of total exercise time (TET) and disease categories of HF to investigate if TET could affect the superiority of HIIT when compared with MICT. METHODS AND RESULTS: An electronic literature search of Pubmed, Embase, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov was performed for this review. 16 studies of 661 patients were finally pooled into quantitative synthesis. The weighted mean difference (WMD) and standard mean difference (SMD) with 95% confidence interval (CI) were calculated for quantitative synthesis of outcomes. HIIT was superior to MICT in improving peak oxygen consumption (Peak VO2) (WMD: 1.68 ml · kg-1 · min-1 95% CI: 0.81 to 2.55 n = 661). The subgroup analysis of TET showed that HIIT was superior to MICT in improving Peak VO2 in "short time" subgroup (WMD: 1.61 ml · kg-1 · min-1 95% CI: 0.45 to 2.77 n = 166) and in "medium time" subgroup (WMD: 1.74 ml · kg-1 · min-1 95% CI: 0.53 to 2.95 n = 420), and that there was no significant difference between HIIT and MICT in improving Peak VO2 in "long time" subgroup (WMD: 0.62 ml · kg-1 · min-1 95% CI: -1.34 to 2.58 n = 75). CONCLUSIONS: The superiority of HIIT to MICT in improving Peak VO2 arose in a short to medium length of TET whereas it was effaced by an increment of TET. This "paradox" of TET on HIIT versus MICT might be due to the increasing poor adherence to target exercise intensity over time. TRIAL REGISTRATION: PROSPERO registration number: CRD42022375076.
Gu et al. (Thu,) conducted a meta-analysis in Heart failure (n=661). High intensity interval training (HIIT) vs. Moderate intensity continuous training (MICT) was evaluated on Peak oxygen consumption (Peak VO2) (WMD 1.68, 95% CI 0.81 to 2.55). High intensity interval training was superior to moderate intensity continuous training in improving peak oxygen consumption (WMD 1.68; 95% CI 0.81-2.55), but this benefit was lost with longer total exercise time.