Peak oxygen uptake (Vo_2peak) strongly predicts mortality in cardiac patients. We compared the effects of aerobic interval training (AIT) versus moderate continuous training (MCT) on Vo_2peak and quality of life after coronary artery bypass grafting (CABG).

Fifty-nine CABG patients were randomized to either AIT at 90% of maximum heart rate or MCT at 70% of maximum heart rate, 5 d/wk, for 4 weeks at a rehabilitation center. Primary outcome was Vo_2peak, at baseline, after rehabilitation (4 weeks), and after 6 months of home-based exercise (6 months).

Vo_2peak increased between baseline and 4 weeks in AIT (27.1 ± 4.5 vs 30.4 ± 5.5 mL·kg⁻¹·min⁻¹, P < .001) and MCT (26.2 ± 5.2 vs 28.5 ± 5.6 mL·kg⁻¹·min⁻¹, P < .001; group difference, not significant). Aerobic interval training increased Vo_2peak between 4 weeks and 6 months (30.4 ± 5.5 vs 32.2 ± 7.0 mL·kg⁻¹·min⁻¹, P < .001), with no significant change in MCT (28.5 ± 5.6 vs 29.5 ± 5.7 mL·kg⁻¹·min⁻¹). Quality of life improved in both groups from baseline to 4 weeks, remaining improved at 6 months. There were no changes in echocardiographic systolic and diastolic left ventricular function. Adiponectin increased between 4 weeks and 6 months in both groups (group differences, not significant).

Four weeks of intense training increased Vo_2peak significantly after both AIT and MCT. Six months later, the AIT group had a significantly higher Vo_2peak than MCT. The results indicate that AIT and MCT increase Vo_2peak similarly in the short term, but with better long-term effect of AIT after CABG.