title: Is long-term exercise intervention effective to improve cardiac autonomic control during exercise in subjects with multiple sclerosis? A randomized controlled trial.
abstract: BACKGROUND
  Patients with multiple sclerosis (MS) suffer from a disturbed cardiac autonomic control during exercise (based on heart rate (HR) changes during exercise), which affects exercise tolerance. Whether long-term exercise intervention improves HR changes during exercise in patients with MS remains unknown.
  
  
  OBJECTIVE
  To examine whether long-term exercise intervention improves HR changes during exercise, and correlates with improvements in exercise tolerance, in patients with MS.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  University rehabilitation facility.
  
  
  METHODS
  Twenty-three patients with MS were randomly assigned to six months of follow-up (n=9) or six months of exercise training (n=14, 54-60 training sessions).
  
  
  METHODS
  At baseline and after three and six months of follow-up, exercise-onset (first 20 and 60 seconds) and -offset (1-minute recovery) heart rate (HR) change was determined during a constant-load exercise test: these data reflect the (re)activation of the (para)sympathetic nervous system at initiation and/or cessation of exercise. Blood lactate, HR, oxygen uptake, expiratory volume and ratings of perceived exertion (RPE) were assessed during exercise as indicators for exercise tolerance.
  
  
  RESULTS
  Exercise-onset and -offset HR and exercise tolerance did not change during follow-up in the control group (P>0.05). In the exercise intervention group, blood lactate content and RPE during exercise decreased significantly (group/time interaction effect P<0.05), but exercise-onset and -offset HR did not change (P>0.05). No correlations were found between changes in exercise tolerance and changes in exercise-onset and -offset HR (P>0.05).
  
  
  CONCLUSIONS
  In patients with MS, long-term exercise intervention does not improve HR changes during exercise, despite improvements in exercise tolerance, indicating that cardiac autonomic control during exercise is not easily improved by exercise intervention in patients with MS.
  
  
  CONCLUSIONS
  This study indicates that patients with MS suffer from a disturbed cardiac autonomic control during exercise, based on heart rate changes, which is not easily remediated by exercise intervention. Because a disturbed cardiac autonomic control is related to exercise intolerance in MS, it should further be explored how to remediate this anomaly through exercise intervention or other approaches.
authors.affiliation: Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium - dominique.hansen@uhasselt.be.
authors.forename: D
authors.initials: D
authors.lastname: Hansen
authors.forename: I
authors.initials: I
authors.lastname: Wens
authors.forename: C
authors.initials: C
authors.lastname: Keytsman
authors.forename: B O
authors.initials: BO
authors.lastname: Eijnde
authors.forename: P
authors.initials: P
authors.lastname: Dendale
mesh_terms: D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000502:physiology / Q000503:physiopathology*; D016009:Chi-Square Distribution; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology / Q000534:rehabilitation*; D011446:Prospective Studies; D012047:Rehabilitation Centers; D013997:Time Factors
chemical_list: D019344:Lactic Acid