Comparison of refractoriness after exercise- and hyperventilation-induced asthma.
To study the relationship of bronchoconstriction and refractoriness we performed pairs of exercise and hyperventilation tests in 15 patients (mean [SEM] age 28.5 [2.8] years) with a history of exercise-induced asthma. Mean (SEM) maximum specific airway resistance (SRaw) increased during the first exercise test to 33.9 (4.5) and during the second exercise test to 29.8 (5.2) cmH2O x s (n.s.). Mean (SEM) maximum specific airway resistance (SRaw) increased during the first hyperventilation test to 44.0 (5.9) and during the second hyperventilation test to 27.4 (3.3) cmH2O x s (p less than 0.01). Mean maximum bronchoconstriction after corresponding exercise and hyperventilation tests did not differ statistically. There was a significantly larger inter-individual variability in the airway response to hyperventilation (p less than 0.001). From these data we suggest that similar refractoriness can be observed after both exercise and hyperventilation.
Nowak
D
D
Krankenhaus Grosshansdorf, Germany.
Kuziek
G
G
Jörres
R
R
Magnussen
H
H
D000293:Adolescent; D000328:Adult; D000403:Airway Resistance / Q000502:physiology; D001250:Asthma, Exercise-Induced / Q000503:physiopathology*; D001985:Bronchial Provocation Tests / Q000379:methods*; D016084:Bronchoconstriction / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D014797:Vital Capacity / Q000502:physiology