Impact of cardiac rehabilitation exercise frequency on exercise capacity in patients with coronary artery disease: a retrospective study.

Cardiac rehabilitation (CR) significantly improves cardiovascular outcomes in patients with coronary artery disease (CAD). International guidelines vary in the minimum recommended frequency of supervised exercise from 1 to 3 sessions per week. This is the first study in the Middle East and North African regions assessing the impact of 2 versus 3 days/week of supervised exercise on peak exercise capacity in patients with CAD. Single-center retrospective cohort study involving 362 patients enrolled in the only CR center in the State of Qatar. Only high-quality data was included by strict evaluation of compliance to the exercise intervention. Fifty patients who underwent a symptom-limited exercise test before and after CR were included (31 patients on 2 days/week, 19 on 3 days/week). No significant differences were observed in baseline characteristics between groups. Exercise intervention differed significantly between groups in exercise training frequency (2 days/week: 1.97 ± 0.2 vs. 3 days/week: 2.7 ± 0.3; p < 0.00). Peak exercise capacity as peak metabolic equivalents of task (MET) significantly increased in both groups (2 days/week: Pre 8.3 ± 2.4 vs. Post 9.4 ± 2.9, p-value 0.00; 3 days/week: Pre 7.4 ± 1.6 vs. Post 8.4 ± 2.0, p-value 0.00). No significant difference was observed between groups for change in Peak Exercise Capacity (2 days/week 1.1 ± 1.1 vs. 3 days/week 1.0 ± 0.9, p = 0.87). When the total number of exercise sessions is equal, supervised exercise frequencies of 2 and 3 days/week may significantly and equally improve peak exercise capacity in patients with CAD.