title: Effects of altered airway function on exercise ventilation in asthmatic adults.
abstract: OBJECTIVE
  Variable airway function is a central feature of the asthmatic condition. Thus, habitually active asthmatics are certain to exercise under conditions of variable airway (dys)function. The purpose of this study was to determine the effects of variable preexercise airway function on ventilation during whole-body exercise in asthmatic adults.
  
  
  METHODS
  Eight mild asthmatic (age = 26 yr; V˙O2peak = 49 mL·kg·min) and nine nonasthmatic (age = 30 yr; V˙O2peak = 46 mL·kg·min) adults performed constant workrate cycling exercise to exhaustion after four separate interventions: 1) a control trial (CON); 2) inhalation of fast-acting β2-agonist (BD); 3) eucapnic voluntary hyperpnea challenge (BC); and 4) sham to the hyperpnea (SHAM). Pulmonary function was assessed at baseline and after each intervention. Exercise ventilation and operating lung volumes were compared among the four exercise trials in both control and asthmatic subjects.
  
  
  RESULTS
  Baseline pulmonary function was significantly lower in asthmatic subjects compared with control subjects. In asthmatic subjects, postintervention (i.e., preexercise) forced expiratory volume 1.0 s was significantly different among the four exercise trials (CON = 3.5 ± 0.4, BD = 4.1 ± 0.4, SHAM = 3.6 ± 0.3, BC = 2.8 ± 0.3 L, P < 0.05), whereas it was not different in control subjects. There were no differences in exercise ventilation or operating lung volumes during exercise among the four trials either within asthmatic subjects or between control and asthmatic subjects.
  
  
  CONCLUSIONS
  These findings suggest that the state of airway function-whether bronchodilated or bronchoconstricted-before exercise in the mild asthmatic does not affect the exercise ventilatory response. Thus, ventilatory system function in the asthmatic appears to be responsive to the acute requirement for increased airflow during whole-body exercise.
authors.affiliation: Department of Environmental and Health Sciences, Johnson State College, Johnson, VT.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rossman
authors.forename: Susan
authors.initials: S
authors.lastname: Nader
authors.forename: Dustin
authors.initials: D
authors.lastname: Berry
authors.forename: Francesca
authors.initials: F
authors.lastname: Orsini
authors.forename: Andrew
authors.initials: A
authors.lastname: Klansky
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Haverkamp
mesh_terms: D000293:Adolescent; D058666:Adrenergic beta-2 Receptor Agonists / Q000627:therapeutic use; D000328:Adult; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D016084:Bronchoconstriction; D001993:Bronchodilator Agents / Q000627:therapeutic use; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008450:Maximal Midexpiratory Flow Rate; D010366:Peak Expiratory Flow Rate; D012123:Pulmonary Ventilation / Q000502:physiology*; D014797:Vital Capacity; D055815:Young Adult
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents