title: Moderate intensity exercise mediates comparable increases in exhaled chloride as albuterol in individuals with cystic fibrosis.
abstract: BACKGROUND
  Despite the demonstrated advantageous systemic changes in response to regular exercise for individuals with cystic fibrosis (CF), exercise is still viewed as an elective rather than a vital component of therapy, and it is likely that these benefits extend to and are partially mediated by exercise-induced changes in ion regulation.
  
  
  OBJECTIVE
  We sought to determine if exercise could provide comparable improvements in ion regulation in the CF lung as albuterol, measured using exhaled breath condensate (EBC) collection and nasal potential difference (NPD).
  
  
  METHODS
  Fourteen CF (13-42 yrs.) and sixteen healthy (18-42 yrs.) subjects completed a randomized crossover study of albuterol and submaximal exercise. EBC was collected at baseline, 30- and 60-min post-albuterol administration, and at baseline and during three separate 15 min cycling exercise bouts at low, moderate, and vigorous intensity (25, 50 and 65% of the maximum workload, respectively). NPD was performed at 30- and 80-min post albuterol or following moderate and vigorous intensity exercise.
  
  
  RESULTS
  CF subjects had lower EBC Cl(-), but no difference in EBC Na(+) at baseline when compared to healthy subjects. EBC Cl(-) increased four-fold with moderate exercise which was similar to that seen 60-min post albuterol administration for CF subjects. Neither exercise nor albuterol altered EBC Na(+). The change in NPD voltage with amiloride (ΔAmil) was greater and there was minimal Cl(-) secretion (ΔTCC) seen at baseline in the CF compared to the healthy subjects. ΔAmil was greater with both albuterol and exercise when compared to baseline within both CF and healthy groups, but there was no significant difference in the ΔTCC response with either treatment.
  
  
  CONCLUSIONS
  Both exercise and albuterol can alter ion regulation increasing Cl(-) secretion to a significant and similar degree in individuals with CF.
authors.affiliation: Department of Pharmacy Practice & Science, University of Arizona, Tucson, AZ, USA; Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: wheatley.courtney@mayo.edu.
authors.forename: Courtney M
authors.initials: CM
authors.lastname: Wheatley
authors.affiliation: Department of Pharmacy Practice & Science, University of Arizona, Tucson, AZ, USA; Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA. Electronic address: baker.sarah@mayo.edu.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Baker
authors.affiliation: Department of Pharmacy Practice & Science, University of Arizona, Tucson, AZ, USA. Electronic address: uagrad06@gmail.com.
authors.forename: Mary A
authors.initials: MA
authors.lastname: Morgan
authors.affiliation: Department of Pharmacy Practice & Science, University of Arizona, Tucson, AZ, USA; Department of Neurology, University of Arizona, Tucson, AZ, USA. Electronic address: mgm2@email.arizona.edu.
authors.forename: Marina G
authors.initials: MG
authors.lastname: Martinez
authors.affiliation: Department of Medicine, University of Alabama, Birmingham, AL, USA. Electronic address: bliu@peds.uab.edu.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Medicine, University of Alabama, Birmingham, AL, USA. Electronic address: smrowe@uab.edu.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Rowe
authors.affiliation: Department of Pediatrics- Pulmonology, Allergy and Immunology, University of Arizona, Tucson, AZ, USA. Electronic address: wjmorgan@arc.arizona.edu.
authors.forename: Wayne J
authors.initials: WJ
authors.lastname: Morgan
authors.affiliation: Department of Pharmacy Practice & Science, University of Arizona, Tucson, AZ, USA. Electronic address: ecwong47@gmail.com.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Wong
authors.affiliation: Department of Pharmacy Practice & Science, University of Arizona, Tucson, AZ, USA. Electronic address: karpen@pharmacy.arizona.edu.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Karpen
authors.affiliation: Department of Kinesiology, University of Minnesota, Minneapolis, MN, USA. Electronic address: esnyder@umn.edu.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Snyder
mesh_terms: D000293:Adolescent; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage / Q000493:pharmacokinetics; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002712:Chlorides / Q000032:analysis*; D018592:Cross-Over Studies; D003550:Cystic Fibrosis / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D004305:Dose-Response Relationship, Drug; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D002712:Chlorides; D000420:Albuterol
keywords: Airway surface liquid; Beta-2 adrenergic receptor (ADBR2); Epithelial sodium channels (ENaC); Exhaled breath condensate (EBC); Nasal potential difference (NPD); Purinergic receptor (P2Y(2))