Circulation. 2017 Jan 12;:
BACKGROUND: -Small studies have suggested that high intensity interval training (HIIT) is superior to moderate continuous training (MCT) in reversing cardiac remodeling and increasing aerobic capacity in heart failure patients with reduced ejection fraction (HFrEF). The present multicenter trial compared 12 weeks supervised interventions of HIIT, MCT, or a recommendation of regular exercise (RRE).
METHODS: -261 patients with LVEF ≤35% and NYHA II-III were randomly assigned to HIIT at 90-95% of maximal heart rate (HRmax), MCT at 60-70% of HRmax or RRE. Thereafter, patients were encouraged to continue exercising on their own. Clinical assessments were performed at baseline, after the intervention, and at follow-up after 52 weeks. Primary endpoint was between groups comparison of change in left ventricular end-diastolic diameter from baseline to 12 weeks.
RESULTS: -Groups did not differ for age (median 60 years), gender (19% women), ischemic etiology (59%), or medication. Change in left ventricular end-diastolic diameter from baseline to 12 weeks was not different between HIIT and MCT, P=0.45; respective changes versus RRE were -2.8 mm (-5.2, -0.4; P=0.02) in HIIT and -1.2 mm (-3.6, 1.2; P=0.34) in MCT. There was also no difference between HIIT and MCT in peak oxygen uptake, P=0.70, but both were superior to RRE. However, none of these changes were maintained at follow-up after 52 weeks. Serious adverse events were not statistically different during supervised intervention or at follow-up at 52 weeks (HIIT 39%, MCT 25%, RRE 34%, P=0.16). Training records showed that 51% of patients exercised below prescribed target during supervised HIIT and 80% above in MCT.
CONCLUSIONS: -HIIT was not superior to MCT in changing left ventricular remodeling or aerobic capacity, and its feasibility remains unresolved in heart failure patients. Clinical Trial Registration-http://www.clinicaltrials.gov Unique identifier: NCT00917046.