Role of lung inflammatory mediators as a cause of training-induced lung function changes in runners

Objective. - This study was designed to assess whether one year endurance training affects lung inflammatory mediators release and airway cells composition, and the possible relationship with lung function disorders in healthy runners. Materials and Methods. - In 10 healthy endurance runners, sputum samples were obtained at rest and 2 h after an exercise session at 80% of athlete's maximal aerobic speed. Inflammatory cells and metabolites were assessed and respiratory function was analysed either after exercise, or at rest through spirometry. The tests were conducted on 3 different occasions: during basic endurance training, pre-competitive and competitive periods. Results. - At rest, sputum showed prevalence of macrophages over neutrophils; after exercise, increased neutrophil counts were found in the two last periods of the sport season (P < 0.05). A significant increase in macrophage counts was observed during the pre-competitive period. Sputum supernatant revealed significant increase in histamine, IL-8, LTB4, and LTE4 concentrations during the competitive period. Conclusion. - This study does not provide significant evidence that one year endurance training may be detrimental for respiratory health in runners. Indeed, in spite of significant changes in airway cells and markers of lung inflammation, no symptoms or changes in lung function were found. (c) 2007 Elsevier Masson SAS. All rights reserved.