title: Does a low-density gas mixture or oxygen supplementation improve exercise training in COPD?
abstract: BACKGROUND
  Low-density gas mixtures and oxygen (O₂) supplementation are known to improve physical performance and ventilatory adaptation during incremental maximal exercise in COPD. We investigated whether their combined use during intense physical training is also effective in ameliorating exercise tolerance in patients affected by moderate to severe COPD.
  
  
  METHODS
  Thirty patients (FEV₁ < 60% of predicted) underwent a 2-month rehabilitation program. Leg-cycle training was conducted thrice weekly at 80% of the initial peak work rate for at least 20 min breathing room air, a 60% helium and 40% O₂ mixture, or supplemental O₂ (40%) inhaled from a Douglas bag. The study was randomized with a double-blind design. Before and at the end of the training period the subjects were tested for spirometry, arterial gas tension, diffusing lung capacity for CO, and incremental and constant work rate exercise test on a cycle ergometer.
  
  
  RESULTS
  Physical training resulted in a significant improvement in peak oxygen consumption and power output (P < .01 for both) and in exercise endurance time (P < .05) independently of the kind of inhaled gas during the rehabilitation program (P ≥ .42). No changes were observed in lung function tests or gas exchange.
  
  
  CONCLUSIONS
  We concluded that the use of a low-density gas mixture or O₂ supplementation does not contribute to improved exercise performance in patients with moderate to severe COPD without a significantly decreased diffusion lung capacity for CO who are able to tolerate intense physical training.
authors.affiliation: Dipartimento di Medicina Interna, Università degli Studi di Genova, Viale Benedetto XV, 6, Genova, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Scorsone
authors.forename: Stefano
authors.initials: S
authors.lastname: Bartolini
authors.forename: Riccardo
authors.initials: R
authors.lastname: Saporiti
authors.forename: Fulvio
authors.initials: F
authors.lastname: Braido
authors.forename: Michele
authors.initials: M
authors.lastname: Baroffio
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pellegrino
authors.forename: Vito
authors.initials: V
authors.lastname: Brusasco
authors.forename: Emanuele
authors.initials: E
authors.lastname: Crimi
mesh_terms: D000368:Aged; D004311:Double-Blind Method; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D006371:Helium / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000008:administration & dosage*; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000534:rehabilitation*; D016896:Treatment Outcome
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen