Resistance exercise training improves heart rate variability and muscle performance: a randomized controlled trial in coronary artery disease patients

Background. Resistance exercise (RE) is an important part of cardiac rehabilitation. However, it is not known about the low intensity of RE training that could modify the heart rate variability (HRV), muscular strength and endurance in patients with coronary artery disease (CAD). Aim. To investigate the effects of high repetition/low load resistance training (HR/LL-RT) program on HRV and muscular strength and endurance in CAD patients. Design. Randomized and controlled trial. Setting. Patients seen at the Cardiopulmonary Physical Therapy Laboratory between May 2011 and November 2013. Population. Twenty male patients with CAD were randomized to a training group (61.3 +/- 5.2 years) or control group (61 +/- 4.4 years). Methods. 1 repetition maximum (1-RM) maneuver, discontinuous exercise test on the leg press (DET-L), and resting HRV were performed before and after 8 weeks of HR/LL-RT on a 45 degrees leg press. RMSSD, SD1, mean HR and ApEn indices were calculated. The HR/LL-RT program consisted of a lower limb exercise using a 45 degrees leg press; 3 sets of 20 repetitions, two times a week. The initial load was set at 30% of the 1-RM load and the duration of the HR/LL-RT program was performed for 8 weeks. Results. After 8 weeks of HR/LL-RT there were significant increases of RMSSD and SD1 indices in the training group only (P<0.05). There was a significant decrease in mean HR after HR/LL-RT in the training group (P<0.05). There was a significantly higher ApEn after in the training group (P<0.05). There were significantly higher values in the training group in contrast to the control group (P<0.05). Conclusion. These results show positive improvements on HRV, as well as muscle strength and endurance in CAD patients. Clinical Rehabilitation Impact. Eight weeks of HR/LL-RT is an effective sufficient to beneficially modify important outcomes as HRV, muscle strength and endurance in CAD patients.