High-Intensity Interval Training Improves Airway Health in Inactive Non-asthmatic Children

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 eight weeks of high-intensity exercise training would improve the airway health of inactive, non-asthmatic prepubescent children. METHODS: Sixteen healthy, prepubescent children were tested (training group [TrG] n=8, control group [ConG] n=8). Subjects wore accelerometers for seven days prior to the 8-week training period to determine activity level. Prior to and following eight weeks of training (or no training), subjects completed pulmonary function tests (PFTs) including forced expiratory flow in 1-sec (FEV1), forced vital capacity, forced expiratory flow at 25-75% of vital capacity (FEF25-75), exhaled nitric oxide (eNO), and impulse oscillometry (IOS). Subjects also completed an incremental cycle VO2max test, eucapnic voluntary hyperventilation (EVH), anthropometric tests, and blood tests to determine fasting blood glucose, total cholesterol, HDL, LDL, and triglycerides. Body composition was determined using dual-energy x-ray absorptiometry (DXA) pre-training and bioelectrical impedance analysis (BIA) pre- and post-training. 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 VO2max (∼24%), and a decrease in total cholesterol (∼13%) and LDL cholesterol (∼35%) following training. Additionally, we found improvements (p<0.05) in ΔFEV1 both post-exercise (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 change in 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 ΔFEV1 following training, and controlling for VO2max lean body mass did not change this association (r=-0.80, p<0.05). CONCLUSION: These results suggest that physical inactivity negatively impacts airway health in non-asthmatic prepubescent children, which can be improved with high-intensity training. However, increased body fat may constrain these improvements.