title: Aerobic exercise training improves autonomic nervous control in patients with COPD.
abstract: OBJECTIVE
  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 lower 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.
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Department of Physiotherapy, Federal University of Sao Carlos, UFSCar, Rodovia Washington Luis, KM 235, Monjolinho, CEP: 13565-905 Sao Carlos, SP, Brazil. audrey@ufscar.br
authors.forename: Audrey
authors.initials: A
authors.lastname: Borghi-Silva
authors.forename: Ross
authors.initials: R
authors.lastname: Arena
authors.forename: Viviane
authors.initials: V
authors.lastname: Castello
authors.forename: Rodrigo Polaquini
authors.initials: RP
authors.lastname: Simões
authors.forename: Luis Eduardo Barreto
authors.initials: LE
authors.lastname: Martins
authors.forename: Aparecida Maria
authors.initials: AM
authors.lastname: Catai
authors.forename: Dirceu
authors.initials: D
authors.lastname: Costa
mesh_terms: D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D005081:Exercise Therapy; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D015397:Program Evaluation; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000534:rehabilitation; D016896:Treatment Outcome