Effects of rowing training on airway responsiveness in asthmatics

Abstract

We previously reported that after a short course of rowing training the responsiveness to methacholine (Mch) in the absence of deep inspiration (DI) decreased in healthy subjects. We assessed whether a similar beneficial effect of exercise on airway responsiveness could occur in asthmatics. Nine patients (M/F: 3/6; mean age±SD: 24±2 yrs) with mild untreated asthma (FEV(1): 100±7.4% pred, FEV(1)/VC 90±6.5%) underwent a series of single dose Mch bronchoprovocations in the absence of DI in the course of a indoor rowing training consisted of two to three sessions per week for 10 weeks (total 28 sessions). Each session included a warm-up period for 20 min (running and stretching), and a specific training on rowing ergometer (Concept II, Morrisville, VT) for 40 to 70 minutes. In order to document power output, strokes, and mean maximal speed for each individual, a 1000-m all-out rowing test was first performed after a 20 min warm-up. Based on the performance, watt stroke-1 and strokes min-1 recorded in the 1000-m all-out test, a certified European rowing coach created personalized training programs. At week 0, 5 and 10, 1000- and 2000-m all-out rowing tests were performed to evaluate performance and re-assess the individualized workload. The 10-week training program included 20% of all training time at maximal power output, 10% of all training time at 75-90% of maximal power output and 70% of all training time at 60-65% of maximal power output. All sessions were supervised by a certified training instructor and a pulmonologist. The single dose Mch was established as the dose able to induce at least 15% reduction in IVC, and was administered to each subject at every challenge occasion. Five asthmatics (M/F: 1/4; mean age±SD: 26±3 yrs) with similar baseline lung function (FEV1: 102±7.0% pred, and FEV(1)/VC: 83±6.0%; p=0.57 and p=0.06, respectively) not participating in the rowing 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), 11±8% at week 10 (p=0.028). The Mch-induced reduction in FEV(1) 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 pre-training). Conversely, Mch-induced reduction in IVC in controls remained unchanged after 10 weeks (% reduction IVC at baseline: 21±20%; after 10 weeks: 29±14%, p=0.28). This study indicates that a short course of rowing training is capable of reducing airway responsiveness in mild asthmatics.