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Lee C.T.1, Wang L.Y.1,2, Chang W.H.1, Yang P.Y.2
1National Taiwan University, College of Medicine, School and Graduate Institute of Physical Therapy, Taipei, Taiwan, 2National Taiwan University Hospital, Physical Therapy Center, Taipei, Taiwan
Background: In patients with chronic obstructive pulmonary disease (COPD), altered breathing pattern and impaired gas exchange could negatively impact autonomic nervous system (ANS) function. ANS dysfunction is a strong predictor of cardiovascular diseases. In patients with COPD, aerobic exercise training results in an improvement of cardiopulmonary fitness; however, its effect on ANS function remains inconclusive.
Purpose: To assess the effectiveness of aerobic exercise training in patients with COPD on ANS function using time and frequency domain analyses of heart rate variability (HRV).
Methods: Randomized controlled trials comparing aerobic exercise training with no-exercise control were identified from updated literature searches of MEDLINE and EMBASE to June, 2016. Outcome measurements included standard deviation of R-R intervals (SDNN), square root of mean of the squared differences between adjacent R-R intervals (RMSSD), high frequency in normalized units (nuHF), low frequency in normalized units (nuLF), and low frequency/high frequency ratio (HF/LF ratio).
Results: This review included three trials, and a total of 85 patients were randomized to aerobic exercise training (n=48) or control (n=37). The mean age of patients in the aerobic exercise training and control group within the trials ranged from 60 to 67 years, and 61 to 67 years, respectively. The mean predicted forced expiratory volume in one second (FEV1, % predicted) within the trials ranged from 32% to 35% in the aerobic exercise training and 35% to 40% in the control group. The aerobic exercise training duration ranged from 4 to 6 weeks. Compared to the control group, aerobic exercise training improved HF/LF ratio (SMD: -0.72 [95% CI: -1.16, -0.27]) and SDNN (SMD: 1.07 [95% CI: 0.53, 1.60]), with no significant difference in RMSSD (SMD: 0.79 [95% CI: -0.07, 1.65]), nuHF (SMD: 0.23 [95% CI: -0.57, 1.03]), and nuLF (SMD: -0.23 [95% CI: -1.20, 0.73]).
Conclusion(s): Aerobic exercise training results in improvement of sympathetic/parasympathetic imbalance in patients with COPD compared with no exercise control group, but its impacts on separate divisions of ANS function remains uncertain.
Implications: Whether the beneficial effect of aerobic exercise training on ANS function could further contribute to risk reduction of cardiovascular diseases in patients with COPD warrants future investigations.
Funding acknowledgements: None
Topic: Cardiorespiratory
Ethics approval: Ethics approval was not required
All authors, affiliations and abstracts have been published as submitted.
