Cadiorespiratory fitness gains in phase 3 cardiac rehabilitation participants - impact of weekly exercise training frequency

Background High cardiorespiratory fitness (CRF) is associated with lower all-cause mortality risk in cardiovascular disease (CVD) patients. Cardiopulmonary exercise testing (CPET) is the gold standard method to assess CRF in CVD patients and it is used to individualize exercise training prescription. Long-term phase III cardiac rehabilitation (CR) programs can feature a variety of exercise modalities and schedules. Understanding how weekly exercise training frequency and attendance rates to exercise CR sessions might affect gains in CRF after 12 months might enhance a better insight on how to provide tailored guidance to patients. Purpose To compare peak oxygen uptake (VO2peak) in CVD patients attending phase III CR exercise sessions either 3 times/week or 2 times/week over 12 months. Methods CVD patients attending for 12 months a phase III CR program were included. VO2peak was assessed through a CPET (cycle ergometer, ramp protocol) at baseline (M0) and after 12 months (M1). After initial screening, patients chose to attend 60 minutes exercise CR sessions either 3 or 2 times/week. Attendance rates were calculated dividing the number of sessions attended by the number of sessions planned. Paired and independent sample t-tests were used (or non-parametric alternatives when applicable). Results One hundred and twelve patients completed 12-months of a phase III exercise-based CR program. Nighty-one patients attended 3 times/week [62±10 years-old, 86.8% male, 87.9% had coronary artery disease (CAD)] and twenty-one attended 2 times/week (66±8 years-old, 71.4% male, 85.7% CAD). Patients attending 3 times/week had improvements in VO2peak between M0 and M1 (M0: 21.22 ± 6.35 ml/kg/min vs. M1: 23.12 ± 7.21 ml/kg/min; p-value < 0.001). Furthermore, comparing the percentage of gains between M0 and M1, patients that attended 3 times/week had more gains in VO2peak (9.65 ± 18.05% vs. 0.59 ± 10.71%; p-value = 0.043) compared to the 2 times/week group. Attendance rates did not differ between groups (68.48 ± 16.64% vs. 72.42 ± 14.05%; p-value=0.159). Conclusion Patients attending a higher number of CR exercise sessions (3 times/week) had a greater improvement in CRF after 12 months on a phase III CR program. Higher attendance rates in patients that choose CR sessions 2 times/week might be crucial to achieve CRF gains. Further analyses are needed to comprehensively understand the impact of weekly exercise training frequency and attendance rates in other health outcomes in long-term CR programs.