High incidence of exercise-induced bronchoconstriction in triathletes of the Swiss national team.
OBJECTIVE
To assess the progression of bronchial reactivity (BR) and incidence of bronchial hyperreactivity (BH), exercise-induced bronchoconstriction (EIB) and asthma in triathletes over 2 years.


METHODS
Subjects were seven athletes from the Swiss national triathlon team (mean (SD) age 24.3 (4.8) years), who initially were not asthmatic, not treated with antiasthmatic medication, and who had performed at international level for more than 3 consecutive years (2001-2003). To assess BR, BH and EIB, subjects ran on a 400 m track for 8 min at intensities equal to the anaerobic threshold. Tests were conducted in ambient temperatures of 4.4 (2.8) degrees C, -8.8 (2.4) degrees C and 3.6 (1.5) degrees C, and humidity of 52 (16)%, 83 (13)% and 93 (2)%. Forced expiratory volume in 1 s (FEV(1)) was measured before and at 2, 5, 10 and 15 min after EIB, and 5 min after inhalation of a beta2 agonist. Two methods were used to calculate the incidence: (1) the standard assessment; (2) extrapolation of the decrease in FEV(1) to the BH limit.


RESULTS
BR increased significantly in the seven athletes (FEV(1): year, p = 0.04; year x EIB, p = 0.002; EIB p<0.001). Within 2 years, BR had increased significantly and even reached BH in some athletes. Three athletes exhibited BH. After extrapolation of the decrease in FEV(1) in all seven athletes, the limit of 10% by definition for BH was determined to occur within 1.77-4.81 years, resulting in 21-57% of athletes with newly developed BH per year.


CONCLUSIONS
Athletes develop EIB quickly, a rate of increase 195-286 times that of the normal rate for development of asthma.
Knöpfli
Bruno H
BH
Alpine Children's Hospital, Davos, Switzerland.
Luke-Zeitoun
Mona
M
von Duvillard
Serge P
SP
Burki
Adrian
A
Bachlechner
Christian
C
Keller
Heidi
H
D000328:Adult; D017677:Age Distribution; D000704:Analysis of Variance; D001250:Asthma, Exercise-Induced / Q000175:diagnosis* / Q000453:epidemiology*; D001982:Bronchial Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology; D003251:Constriction, Pathologic / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D018450:Disease Progression; D005080:Exercise Test; D005260:Female; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008297:Male; D011336:Probability; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D013177:Sports; D013557:Switzerland / Q000453:epidemiology