title: Greater endurance capacity and improved dyspnoea with acute oxygen supplementation in idiopathic pulmonary fibrosis patients without resting hypoxaemia.
abstract: Supplemental oxygen is commonly prescribed in patients with idiopathic pulmonary fibrosis (IPF), although its benefits have not been proven. The aims of this study were to investigate the effect of oxygen on oxidative stress, cytokine production, skeletal muscle metabolism and physiological response to exercise in IPF.
  
  
  
  Eleven participants with IPF received either oxygen, at an FiO2of 0.50, or compressed air for 1 h at rest and during a cycle endurance test at 85% of peak work rate. Blood samples collected at rest and during exercise were analysed for markers of oxidative stress, skeletal muscle metabolism and cytokines. The protocol was repeated a week later with the alternate intervention.
  
  
  
  Compared with air, oxygen did not adversely affect biomarker concentrations at rest and significantly improved endurance time (mean difference = 99 ± 81s, P = 0.002), dyspnoea (-1 ± 1 U, P = 0.02), systolic blood pressure (BP; -11 ± 11 mm Hg, P = 0.006), nadir oxyhaemoglobin saturation (SpO2; 8 ± 6%, P = 0.001), SpO2at 2-min (7 ± 6%, P = 0.003) and 5-min isotimes (5 ± 3, P < 0.001) and peak exercise xanthine concentrations (-42 ± 73 µmol/L, P = 0.03). Air significantly increased IL-10 (5 ± 5 pg/mL, P = 0.04) at 2-min isotime. Thiobarbituric acid-reactive substances (TBARs), IL-6, TNF-α, creatine kinase, lactate, heart rate and fatigue did not differ between the two interventions at any time point.
  
  
  
  In patients with IPF, breathing oxygen at FiO2of 0.50 at rest seems safe. During exercise, oxygen improves exercise tolerance, alleviates exercise-induced hypoxaemia and reduces dyspnoea. A potential relationship between oxygen administration and improved skeletal muscle metabolism should be explored in future studies.
authors.affiliation: Discipline of Physiotherapy, La Trobe University, Alfred Centre, Melbourne, Victoria, Australia.|Department of Respiratory & Sleep Medicine, Austin Health, Melbourne, Victoria, Australia.|Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.|Department of Physiotherapy, Austin Health, Melbourne, Victoria, Australia.
authors.forename: Leona M
authors.initials: LM
authors.lastname: Dowman
authors.affiliation: Department of Respiratory & Sleep Medicine, Austin Health, Melbourne, Victoria, Australia.|Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.|Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Christine F
authors.initials: CF
authors.lastname: McDonald
authors.affiliation: School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Bozinovski
authors.affiliation: School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia.
authors.forename: Ross
authors.initials: R
authors.lastname: Vlahos
authors.affiliation: Discipline of Physiotherapy, La Trobe University, Alfred Centre, Melbourne, Victoria, Australia.|Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Gillies
authors.affiliation: Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.|School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia.
authors.forename: Dodie
authors.initials: D
authors.lastname: Pouniotis
authors.affiliation: Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.|Department of Physiotherapy, Austin Health, Melbourne, Victoria, Australia.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Hill
authors.affiliation: Department of Respiratory & Sleep Medicine, Austin Health, Melbourne, Victoria, Australia.|Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.
authors.forename: Nicole S L
authors.initials: NSL
authors.lastname: Goh
authors.affiliation: Discipline of Physiotherapy, La Trobe University, Alfred Centre, Melbourne, Victoria, Australia.|Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia.|Department of Physiotherapy, Alfred Health, Melbourne, Victoria, Australia.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Holland
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D004417:Dyspnea / Q000503:physiopathology; D015444:Exercise / Q000502:physiology; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D000860:Hypoxia; D054990:Idiopathic Pulmonary Fibrosis / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D016753:Interleukin-10 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology; D018384:Oxidative Stress / Q000502:physiology; D010102:Oxygen Inhalation Therapy; D012146:Rest; D016037:Single-Blind Method
chemical_list: D016753:Interleukin-10
keywords: exercise; idiopathic pulmonary fibrosis; metabolism; oxidative stress; oxygen