Airway hyperresponsiveness in elite athletes

It has been suggested that high-level training could contribute to the deve lopment of airway hyperresponsiveness (AHR), but the comparative effects of different sports on airway function remains to be determined. We evaluated 150 nonsmoking volunteers 18 to 55 yr of age; 100 athletes divided into fo ur subgroups of 25 subjects each according to the predominant estimated hyd rocaloric characteristic of ambient air inhaled during training: dry air (D A), cold air (CA), humid air (HA) and a mixture of dry and humid air (MA), and 50 sedentary subjects. Each subject had a respiratory questionnaire, a methacholine challenge, allergy skin-prick tests, and heart rate variabilit y recording for evaluation of parasympathetic tone. The athletes had a 49% prevalence of AHR (PC20 < 16 mg/ml), with a mean PC20 of 16.9 mg/ml, compar ed with 28% (PC20: 35.4) in sedentary subjects (p = 0.009). The prevalence (%) of AHR and mean PC,, (mg/ml) varied as followed in the four subgroups o f athletes: DA: 32% and 30.9; CA: 52% and 15.8; HA: 76% and 7.3; and MA: 32 % and 21.5 (p = 0.002). The estimated parasympathetic tone was higher in at hletes (p < 0.001), but this parameter showed only a weak correlation with PC20 (r = -0.17, p = 0.04). This study has shown a significantly higher pre valence of AHR in athletes than in the control group because of the higher prevalence in the CA and HA groups. Parasympathetic activity may act as mod ulator of airway responsiveness, but the increased prevalence of AHR in our athlete population may be related to the type and possibly the content of inhaled air during training.