Differences in lung function, bronchial hyperresponsiveness and respiratory health between elite athletes competing in different sports

The aim of this study was to examine lung function, bronchial hyperresponsiveness (BHR) and exercise-induced respiratory symptoms in elite athletes performing different sports. Norwegian national-team athletes (30 swimmers, 32 cross-country skiers, 16 speed-skaters, 11 rowers/paddlers, 17 handball players and 23 soccer players) completed a validated questionnaire, measured exhaled nitric oxide (FE_NO), spirometry, methacholine provocation (PD_20met) and skin prick test. Three cut-off levels defined BHR; i.e. PD_20met ≤2 µmol, ≤4 µmol and ≤8 µmol. Mean forced vital capacity (FVC) was highest in swimmers (Mean z-score[95%CI]  = 1.16 [0.80, 1.51]), and close to or higher than reference values according to the Global Lung Initiative equation, across all sports. Mean forced expiratory volume in 1 s (FEV₁) was higher than reference values in swimmers (0.48 [0.13, 0.84]), and ball game athletes (0.69 [0.41, 0.97]). Mean forced expiratory flow between 25 and 75% of FVC (FEF_25–75), and/or FEV₁/FVC were lower than reference values in all endurance groups. BHR defined by ≤2 and ≤8 µmol methacholine was observed in respectively 50%–87% of swimmers, 25%–47% of cross-country skiers, 20%–53% of speed-skaters, 18%–36% of rowers/paddlers, and 0%–17% of the ball game athletes. Exercise-induced symptoms were common in all groups, most frequent in cross-country skiers (88%), swimmers (83%) and speed-skaters (81%).