High-intensity training improves airway responsiveness in inactive nonasthmatic children: evidence from a randomized controlled trial

Abstract

Purpose: the relationship between physical activity and airway health in children is not well understood. The purpose of this study was to determine whether 8 wk of high-intensity exercise training would improve airway responsiveness in prepubescent, nonasthmatic, inactive children. Methods: 16 healthy, prepubescent children were randomized [training group (TrG) n = 8, control group (ConG) n = 8]. Prior to and following 8 wk of training (or no training), children completed pulmonary function tests (PFTs): forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), forced expiratory flow at 25–75% of vital capacity (FEF25–75), and exhaled nitric oxide (FENO). Children completed an incremental cycle V̇o2maxtest, eucapnic voluntary hyperventilation (EVH), anthropometric tests, and blood tests to determine fasting blood glucose, total cholesterol, HDL, LDL, and triglycerides. Body fat percentage was determined using dual-energy X-ray absorptiometry pretraining and bioelectrical impedance pre- and posttraining. Results: there were no differences ( P > 0.05) in anthropometric measures or PFTs between TrG and ConG at baseline. In the TrG, there was a significant increase in V̇o2max(∼24%) and a decrease in total cholesterol (∼13%) and LDL cholesterol (∼35%) following training. There were improvements ( P < 0.05) in ΔFEV1both postexercise (pre: −7.60 ± 2.10%, post: −1.10 ± 1.80%) and post-EVH (pre: −6.71 ± 2.21%, post: −1.41 ± 1.58%) with training. The ΔFEF25–75pre-post exercise also improved with training (pre: −16.10 ± 2.10%, post: −6.80 ± 1.80%; P < 0.05). Lower baseline body fat percentages were associated with greater improvements in pre-post exercise ΔFEV1following training ( r = −0.80, P < 0.05). Conclusion: these results suggest that in nonasthmatic prepubescent children, inactivity negatively impacts airway responsiveness, which can be improved with high-intensity training. Excess adiposity, however, may constrain these improvements.