title: Breathing pattern adopted by children with cystic fibrosis with mild to moderate pulmonary impairment during exercise.
abstract: BACKGROUND
  It is well known that severe lung impairment in cystic fibrosis (CF) may compromise respiratory muscle function at rest. Even though patients with CF and severe obstructive lung disease exhibit an abnormal breathing pattern during exercise (due to expiratory flow limitation), patients with CF and normal lung function reportedly have a normal breathing pattern.
  
  
  OBJECTIVE
  The aim of the study was to assess the precise characteristics of the ventilatory pattern adopted during exercise by children with CF and mild to moderate lung disease.
  
  
  METHODS
  Nine children diagnosed as having mild to moderate CF and 9 healthy children with a similar age distribution participated in this study. Both groups performed a continuous incremental cycling protocol. Breathing and timing components were assessed during exercise.
  
  
  RESULTS
  Differences in the breathing pattern between children with CF and controls during exercise are illustrated in Hey plot which described a rapid shallow breathing pattern in children with CF. During exercise, children with CF showed a significantly lower mean inspiratory flow than healthy children (p < 0.001), whereas the mean expiratory flow was higher (p < 0.001). Children with CF also showed a significant increase in the end-tidal carbon dioxide pressure, which may indicate the emergence of hypercapnia.
  
  
  CONCLUSIONS
  During exercise, children with CF (even those not suffering from advanced disease) showed signs of rapid, shallow breathing and an increase in the ventilatory response. This was essentially due to an increase in the mean inspiratory flow, which in turn suggests an expiratory flow limitation. The children were also predisposed to hypercapnia.
authors.affiliation: EA 3300, APS et Conduites Motrices: Adaptations et Réadaptations, Faculté des Sciences du Sport, Université Picardie Jules Verne, Amiens, France. david.keochkerian@u-picardie.fr
authors.forename: David
authors.initials: D
authors.lastname: Keochkerian
authors.forename: Mehdi
authors.initials: M
authors.lastname: Chlif
authors.forename: Stéphane
authors.initials: S
authors.lastname: Delanaud
authors.forename: Rémi
authors.initials: R
authors.lastname: Gauthier
authors.forename: Yves
authors.initials: Y
authors.lastname: Maingourd
authors.forename: Said
authors.initials: S
authors.lastname: Ahmaidi
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D016022:Case-Control Studies; D002648:Child; D003550:Cystic Fibrosis / Q000150:complications / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D015656:Respiratory Mechanics / Q000502:physiology*; D013147:Spirometry