Comparison between Moderate-high Interval Training and Continuous Training in a Real-life Cardiac Rehabilitation Program - 6 Monhts Follow-up

Background: It has been postulated that interval training is superior to the traditional continuous training in cardiac rehabilitation (CR). Yet, most of studies included heart failure patients, relatively small sample sizes, and diverse training methodologies. The purpose was to compare between interval and continuous training in: peakVO₂, hemodynamics, blood lipids, body composition, quality of life (QOL), and LV function, over 6 months follow-up, in a real-life CR setting.

Following 4 weeks of adjustment in the CR, 84 coronary artery disease patients were randomly assigned to an interval exercise group (IE) or a continuous exercise group (CE). Measurements were obtained at baseline, after 12 weeks of training, and at 9 months. The IE group performed 2 min of low intensity (40-60% VO₂max) followed by 2 min of moderate-high intensity (60-85% VO₂max) for 38 min total; while the CE group exercised for 41 min continuously at a moderate intensity (50-60% VO₂max).

Both groups increased their VO₂peak significantly after training, with no differences between them. Maximal load improved significantly more in the IE group. HbA1c% and hs-CRP were reduced in the IE group alone. Both groups demonstrated substantial but similar improvements in weight, body mass index, resting heart rate, and QOL variables. Regardless of training modality, subjects with normal diastolic function have reached significantly higher levels of peakVO₂. At 9 months, peakVO₂ remained significantly higher vs. baseline only within the IE group, especially among those who stayed in the CR program during the follow-up.

Conclusion: interval training does not seem to elicit higher peakVO₂, but it may have some superiority over continuous training in performing daily activities. Furthermore, favorable changes were preserved for 6 months following interval training, especially if a structured exercise program was maintained. Overall, a 12-week CR program resulted in favorable physiological and psychological outcomes.