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

Purpose 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 ). Methods 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 ( VO 2 peak ). Results 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 VO 2 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. Conclusion Both training programs were equally effective in improving QoL and functional capacity in CHF patients. Trial registration ( http://www.ensaiosclinicos.gov.br /): RBR-6hk9p6; registered on 15 May 2013.