High-intensity interval training is effective and superior to moderate continuous training in patients with heart failure with preserved ejection fraction: A randomized clinical trial

Background: Heart failure with preserved ejection fraction (HFpEF) is a prevalent syndrome, with exercise intolerance being one of its hallmarks, contributing to worse quality of life and mortality. High-intensity interval training is an emerging training option, but its efficacy in HFpEF patients is still unknown. Design: Single-blinded randomized clinical trial. Methods: Single-blinded randomized clinical trial with exercise training 3 days per week for 12 weeks. HFpEF patients were randomly assigned to high-intensity interval training or moderate continuous training. At baseline and after 12 week follow-up, patients underwent clinical assessment, echocardiography and cardiopulmonary exercise testing (CPET). Results: Mean age was 60 +/- 9 years and 63% were women. Both groups (N = 19) showed improved peak oxygen consumption (VO2), but high-intensity interval training patients (n = 10) had a significantly higher increase, of 22%, compared with 11% in the moderate continuous training (n = 9) individuals (3.5 (3.1 to 4.0) vs. 1.9 (1.2 to 2.5) mL.kg(-1).min(-1), p < 0.001). Ventilatory efficiency and other CPET measures, as well as quality of life score, increased equally in the two groups. Left ventricular diastolic function also improved with training, reflected by a significant reduction in E/e' ratio by echocardiography (-2.6 (-4.3 to -1.0) vs. -2.2 (-3.6 to -0.9) for high-intensity interval training and moderate continuous training, respectively; p < 0.01). There were no exercise-related adverse events. Conclusions: This randomized clinical trial provided evidence that high-intensity interval training is a potential exercise modality for HFpEF patients, being more effective than moderate continuous training in improving peak VO2. However, the two strategies were equally effective in improving ventilatory efficiency and other CPET parameters, quality of life score and diastolic function after 3 months of training.