Effect of maximal-intensity and high-intensity interval training on exercise capacity and Quality of life in patients with acute myocardial infarction: a randomized controlled trial

BACKGROUND: An increase in VO2max is important for acute myocardial infarction morbidity, and recurrence rate and intensity have been suggested as important factors in improving VO2max.AIM: The aim of this study was to compare the effects of maximal-intensity interval training (MIIT) and high-intensity interval training (HIIT) on exercise capacity and health-related Quality of Life (HRQoL) in patients with acute myocardial infarction (MI) at low and moderate cardiac risk in cardiac rehabilitation (CR). This study secondarily aimed to compare the effects of hospital-based phase II CR and usual care.DESIGN: This study is a randomized controlled trial.SETTING: Outpatient Rehabilitation Setting.POPULATION: Fifty-nine patients with acute MI were randomly assigned to the MIIT (N.=30) or HIIT (N.=29) group, and 32 to the usual care group.Methods: Twice a week, an intervention was conducted for nine weeks in all groups. The maximum oxygen intake (VO2max) and MacNew Heart Disease HRQoL were evaluated before and after intervention.Results: A significant interaction was observed between time and group for VO2max (P<0.001). The MIIT group showed greater improvement than those exhibited by the HIIT and usual care groups (P<0.05). Similarly, a significant time and group interaction was observed on the MacNew Global, Physical, and Emotional scales (P<0.05), but not on the social scale (P>0.05).Conclusions: Compared to HIIT and usual care, MIIT significantly increased the VO2max and was as safe as HIIT in patients with acute MI with low and moderate cardiac risk in CR. Additionally, MIIT and HIIT were superior to usual care in terms of improving the HRQoL.