Introduction: Asthma is frequently reported in endurance athletes, particularly in cross-country skiers. It has been reported that an exercise field test performed with the competitive type of exercise is the better for diagnosing asthma and bronchial hyperresponsiveness in athletes than bronchial provocation with methacholine.
Objective: The main objective was to compare an exercise field test consisting of a skiing competition with methacholine bronchial provocation in the diagnosis of asthma and bronchial hyperresponsiveness among skiers.
Methods: Twenty-four elite cross-country skiers from the Norwegian national teams (males/females = 16/8) were included in the study. The cumulative dose of inhaled methacholine causing a 20% fall in forced expiratory volume in 1 s (FEV1) (PD20) was compared with reduction in lung function (FEV1) >or= 10% from before to after an exercise field test consisting of a cross-country skiing competition, 10 km (males) and 7 km (females), respectively.
Results: Nine out of 24 (37.5%) athletes experienced a positive methacholine test (PD20 < 8 micromol) (2 females and 7 males), whereas only 2 of the 24 subjects (8.3%) had reductions in FEV1 >or= 10% after the exercise field test. A significant negative correlation was found between age and bronchial responsiveness, r = -0.47, P = 0.02.
Conclusion: The methacholine bronchial provocation test is more sensitive than a sport specific exercise field test for identifying athletes with asthma and/or bronchial hyperresponsiveness.