Effects Of Exercise Training On Airway Closure In Asthmatics

Scichilone N, Morici G, Zangla D, Arrigo R, Cardillo I, Bellia V, Bonsignore MR. Effects of exercise training on airway closure in asthmatics. J Appl Physiol 113: 714-718, 2012. First published June 28, 2012; doi: 10.1152/japplphysiol.00529.2012.-We previously reported that responsiveness to methacholine (Mch) in the absence of deep inspiration (DI) decreased in healthy subjects after a short course of exercise training. We assessed whether a similar beneficial effect of exercise on airway responsiveness could occur in asthmatics. Nine patients (male/female: 3/6; mean age +/- SD: 24 +/- 2 yr) with mild untreated asthma [forced expiratory volume in 1 s (FEV1): 100 +/- 7.4% pred; FEV1/vital capacity (VC): 90 +/- 6.5%] underwent a series of single-dose Mch bronchoprovocations in the absence of DI in the course of a 10-wk training rowing program (6 h/wk of submaximal and maximal exercise), at baseline (week 0), and at week 5 and 10. The single-dose Mch was established as the dose able to induce >= 15% reduction in inspiratory vital capacity (IVC) and was administered to each subject at every challenge occasion. Five asthmatics (male/ female: 1/4; mean age +/- SD: 26 +/- 3 yr) with similar baseline lung function (FEV1: 102 +/- 7.0% predicted; FEV1/VC: 83 +/- 6.0%; P = 0.57 and P = 0.06, respectively) not participating in the exercise training program served as controls. In the trained group, the Mch-induced reduction in IVC from baseline was 22 +/- 10% at week 0, 13 +/- 11% at week 5 (P = 0.03), and 11 +/- 8% at week 10 (P = 0.028). The Mch-induced reduction in FEV1 did not change with exercise (P = 0.69). The reduction in responsiveness induced by exercise was of the same magnitude of that previously obtained in healthy subjects (50% with respect to pretraining). Conversely, Mch-induced reduction in IVC in controls remained unchanged after 10 wk (% reduction IVC at baseline: 21 +/- 20%; after 10 wk: 29 +/- 14%; P = 0.28). This study indicates that a short course of physical training is capable of reducing airway responsiveness in mild asthmatics.