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

Rosenkranz SK, Rosenkranz RR, Hastmann TJ, Harms CA. High-intensity training improves airway responsiveness in inactive nonasthmatic children: evidence from a randomized controlled trial. J Appl Physiol 112: 1174-1183, 2012. First published January 12, 2012; doi:10.1152/japplphysiol.00663.2011.-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 (V) over dot O-2max test, 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 (V) over dot O-2max (similar to 24%) and a decrease in total cholesterol (similar to 13%) and LDL cholesterol (similar to 35%) following training. There were improvements (P < 0.05) in Delta FEV1 both 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 Delta FEF25-75 pre-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 Delta FEV1 following 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.