Exercise-based cardiac rehabilitation increases peak oxygen uptake (peak VO₂), which is the most important prognostic factor in cardiac patients. However, the most effective training strategies (interval training (IT) or moderate continuous training (MCT)) have yet to be identified in coronary artery disease patients. Our objective was to compare the effectiveness and the tolerance of those two modes of exercise during cardiac rehabilitation after an acute coronary syndrome (ACS) in a large single-center randomized study.

F July 2014 to April 2015, one hundred and three patients (88% male, mean age 62 years, mean LVEF 56%) performed 20 sessions, 2-3 sessions/week, including 35min of biking, after a randomization to either high-intensity IT (6 cycles of 2min at 90% peak VO₂ alternating with active recovery) or to MCT (at 1^st ventilatory threshold).

Baseline characteristics between the 2 groups (49 in IT and 54 in MCT) were comparable. Both exercise programs demonstrated significant positive effects on aerobic capacity. Compared to MCT, IT program tended to increase more the peak VO₂ and the peak workload (weighted mean difference+4±3.3 vs+2.7±4mL/kg/min, p=0.06 and+27.7±17 vs+22.8±14.6 Watt, p=0.09 respectively). No adverse event was reported during training sessions.

Interval Training was more effective for the improvement of peak VO₂ than MCT.