title: Oxygen supplementation before or after submaximal exercise in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Evidence for improved exercise tolerance or relief of breathlessness by short term use of oxygen before or after exercise in patients with chronic obstructive pulmonary disease (COPD) is scant, and guidelines for this treatment are lacking despite widespread provision in the UK.
  
  
  METHODS
  The effect of oxygenation either before or after exercise on perception of breathlessness and walk distance was studied in a group of patients with moderate to severe COPD (mean forced expiratory volume in 1 second (FEV(1)) 34% of predicted, mean 6 minute walk distance on air 283 m), all of whom desaturated by at least 4% on submaximal exercise. Oxygen (28%) or air was delivered double blind and in random order, either for 5 minutes before a standard 6 minute walk test (n=34) or for 5 minutes following the end of the test (n=18). Exercise tolerance was measured as the distance achieved and breathlessness was assessed using visual analogue scales (VAS) which were scored before and after exercise and during recovery.
  
  
  RESULTS
  No increase in mean walk distance after oxygen (288 v 283 m) and no improvement in mean breathlessness scores (58 v 54 mm) or recovery times occurred with oxygen taken either before (177 v 184 seconds) or after exercise (182 v 151 seconds).
  
  
  CONCLUSIONS
  This group of patients with COPD derived no physiological or symptomatic benefit from oxygen breathed for short periods before or after submaximal exercise. Domiciliary oxygen should only be prescribed for such patients if they have shown objective evidence of benefit on exercise testing.
authors.affiliation: Department of Respiratory Medicine, Charing Cross Hospital, London W6 8RF, UK.
authors.forename: K
authors.initials: K
authors.lastname: Nandi
authors.forename: A A
authors.initials: AA
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Crawford
authors.forename: K D
authors.initials: KD
authors.lastname: MacRae
authors.forename: R
authors.initials: R
authors.lastname: Garrod
authors.forename: W A
authors.initials: WA
authors.lastname: Seed
authors.forename: C M
authors.initials: CM
authors.lastname: Roberts
mesh_terms: D000368:Aged; D004311:Double-Blind Method; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D010100:Oxygen / Q000627:therapeutic use*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000628:therapy*
chemical_list: D010100:Oxygen