Introduction:

Patients with chronic obstructive pulmonary disease (COPD) may have autonomic nervous system neuropathies with resultant alterations in heart rate variability (HRV). Additionally, right heart failure is frequently a long-term outcome for these patients. Studies have demonstrated improvements in HRV and cardiac function, with exercise-training, in patients with other chronic illnesses. It was the purpose of this study to determine if aerobic exercise-training will improve HRV and right heart function in patients with COPD.

Methods:

Ten subjects diagnosed with COPD, recruited from an outpatient pulmonary rehabilitation program, formed the Exercise Group (EG). These subjects exercised for 8 weeks, 3 times/week, 90 minutes each day, including a 45 minute upper body exercise/coordinated breathing class and a 45 minute aerobic exercise. Ten non-exercising subjects with COPD matched for height, weight and lung function served as the Control Group (CG). HRV (PNN50, RMSSD and SDNN), derived from 24-hour Holter monitoring, and right ventricular ejection fraction (RVEF), measured by echocardiographic imaging, were assessed prior to and following participation in the program.

Results:

Repeated measures ANOVA with post hoc Bonferroni pairwise analyses revealed: significant increases in SDNN (88.1 +/- 32.7 to 113.4 +/- 38.3 ms; P = 0.001), RMSSD (18.1 +/- 7.3 to 40.5 +/- 24.7 ms; P = 0.003), and PNN50 (1.7 +/- 2.5 to 4.9 +/- 4.8 ms; P = 0.017) for EG subjects, following participation in the training program; significant decreases in SDNN (105.4 +/- 31.0 to 88.1 +/- 19.9 ms; P = 0.018) and RMSSD (51.6 +/- 27.9 to 32.5 +/- 13.0 ms; P = 0.017) with no significant change in PNN50 for CG subjects over the same time period; no significant change in RVEF (48.7 +/- 15.1 to 53.2 +/- 13.5 %; P = 0.011) for the EG subjects following participation in the training program; a significant decrease in RVEF for the CG subjects (55.6 +/- 12.7 to 43.9 +/- 8.3 %; P = 0.026) over the same time period.

Conclusions:

These findings suggest that participation in an 8-week aerobic exercise training program improves autonomic nervous system function and preserves right heart function in a direction consistent with other exercise-trained populations.