Our results show increased inflammatory cells in the sputum of endurance athletes, when BHR athletes were compared with non-BHR athletes and control subjects. This does not exclude, however, the possibility that other mechanisms may also be involved but emphasizes the role of airway inflammation in BHR athletes. Both eosinophilic and neutrophilic patterns of bronchial inflammation have previously been reported in the sputum of endurance athletes.
Increased total cell and lymphocyte counts in BAL fluid, and an infiltration by lymphocytes, eosinophils, and neutrophils of the submucosa have also been observed in specimens obtained from bronchial biopsies performed in cross-country skiers. Although an increased neutrophil count has been proposed as a specific feature of airway inflammation in endurance athletes, the BHR+ athletes in the present study showed an airway inflammation with increased eosinophil counts but normal neutrophil counts.
Several factors may contribute to airway neutrophilia, such as prolonged and intense acute exercise or respiratory tract infection. The absence of respiratory tract infection at the time of the experiment, as well as the absence of undergoing an intense training session for at least 48 h before laboratory investigations, may explain the normal neutrophil counts in our study. Although normal exhaled NO levels have been occasionally reported in skiers with “ski asthma,” as in nonasthmatic runners, high exhaled NO concentrations were also observed in atopic skiers and atopic asthmatic subjects.
The increased NO values observed in BHR+ athletes in the present study may be related to the more prevalent atopic status in this group. Hence, our results suggest that the airway inflammation profile in BHR+ athletes presents characteristics that are similar to those encountered in athletes with atopic asthma. However, the clinical characteristics of our athletes population rule out the presence of an associated allergic asthma.