title: Effect of physical training on airway inflammation in bronchial asthma: a systematic review.
abstract: BACKGROUND
  The majority of the global population cannot afford existing asthma pharmacotherapy. Physical training as an airway anti-inflammatory therapy for asthma could potentially be a non-invasive, easily available, affordable, and healthy treatment modality. However, effects of physical training on airway inflammation in asthma are currently inconclusive. The main objective of this review is to summarize the effects of physical training on airway inflammation in asthmatics.
  
  
  METHODS
  A peer reviewed search was applied to Medline, Embase, Web of Science, Cochrane, and DARE databases. We included all observational epidemiological research studies and RCTs. Studies evaluating at least one marker of airway inflammation in asthmatics after a period of physical training were selected. Data extraction was performed in a blinded fashion. We decided a priori to avoid pooling of the data in anticipation of heterogeneity of the studies, specifically heterogeneity of airway inflammatory markers studied as outcome measures.
  
  
  RESULTS
  From the initial 2635 studies; 23 studies (16 RCTs and 7 prospective cohort studies) were included. Study sizes were generally small (median sample size = 30). There was a reduction in C-reactive protein, malondialdehyde, nitric oxide, sputum cell counts and IgE in asthmatics with physical training. Mixed results were observed after training for fractional excretion of nitric oxide and bronchial hyperresponsiveness. The data was not pooled owing to significant heterogeneity between studies, and a funnel plot tests for publication bias were not performed because there were less than 10 studies for almost all outcome measures. Physical training intervention type, duration, intensity, frequency, primary outcome measures, methods of assessing outcome measures, and study designs were heterogeneous.
  
  
  CONCLUSIONS
  Due to reporting issues, lack of information and heterogeneity there was no definite conclusion; however, some findings suggest physical training may reduce airway inflammation in asthmatics.
authors.affiliation: The Ottawa Hospital, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada. spakhale@ohri.ca
authors.forename: Smita
authors.initials: S
authors.lastname: Pakhale
authors.forename: Vanessa
authors.initials: V
authors.lastname: Luks
authors.forename: Andrew
authors.initials: A
authors.lastname: Burkett
authors.forename: Lucy
authors.initials: L
authors.lastname: Turner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D002097:C-Reactive Protein / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D011014:Pneumonia / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D009569:Nitric Oxide; D007073:Immunoglobulin E; D008315:Malondialdehyde; D002097:C-Reactive Protein