Comparative effects of high intensity interval training versus moderate intensity continuous training on quality of life in patients with heart failure: Study protocol for a randomized controlled trial

To compare the effect of high intensity interval training (HIIT) and moderate intensity continuous training (MICT) on physical fitness and quality of life (QoL) in patients with chronic heart failure (CHF). Twenty-two male CHF patients (LVEF < 45%, mean age 53.8 ± 8 yr) were studied before and after 12 weeks of supervised aerobic training for 60 min, three times a week. Patients were randomly (1:1) to MICT (n = 10) and HIIT (n = 12). Both training programs involved treadmill exercise. The group MICT at 75% of peak heart rate (HR) and HIIT at ≈ 95% of peak HR. Outcome measurements included an assessment of QoL (Minnesota Living with Heart Failure Questionnaire (MLHFQ) and SF-36), measurements of 6-min walk test (6MWT) and peak oxygen consumption (VO2 peak). Exercise was associated with a significant increased of 6MWT in 19.4% and 23.1% from MCIT and HIIT, respectively (p < 0.001), but not between-group differences. It was observed an improvement in VO2 peak by 11.2% in the HIIT group and 8.3% in the MCIT group, with between-group differences (p < 0.01). Quality of life improved significantly and in all domains in both groups (p-value time-effect). All patients showed significant improvements in all domains from baseline, it was observed in both groups (p < 0.05), with between-group differences for functional capacity (SF-36). No changes were observed in pain (SF-36) for both groups. Both training programs were equally effective in improving QoL and functional capacity in CHF patients. (http://www.ensaiosclinicos.gov.br/): RBR-6hk9p6; registered on 15 May 2013.