Aerobic exercise training improves autonomic nervous control in patients with COPD

Objectives: Autonomic modulation is adversely impacted in patients with chronic obstructive pulmonary disease (COPD). The purpose of the present investigation is to assess the effects of a 6-week aerobic exercise training program on autonomic modulation of heart rate in patients with COPD. Methods: Forty patients of both sexes with moderate-to-severe COPD were randomly allocated to aerobic exercise training (PT, n = 20) or to usual care (Control, n = 20). The training program consisted of tower and upper limb stretching and 30 min of treadmill. exercise, 3 times per week for a 6-week period. Physiological data during symptom-limited exercise testing and the six-minute walk test (6MWT) were assessed. In addition, R-R intervals were obtained at rest and during the 6MWT. Heart rate variability was analyzed by time (rMSSD and SDNN index) and frequency domains (high frequency - HF, low frequency - LF and HF/LF ratio). Results: Peak oxygen consumption significantly improved in the training group only (p < 0.05). Moreover, the training group demonstrated significant improvements (p < 0.05) in blood lactate, minute ventilation, dyspnea at peak exercise, sympathetic activity, and parasympathetic activity at rest and during submaximal exercise. Lastly, a positive and significant correlation was found between change in 6MWT distance and rMSSD index (r = 0.65 and p = 0.001). Conclusions: Neural control of heart rate, in addition to other clinically valuable measures, is positively altered in moderate-severe COPD patients following 6 weeks of aerobic exercise training. The improvement in submaximal performance after exercise training was associated with parasympathetic activity. Published by Elsevier Ltd.