Body Composition And Physical Activity Impact Airway Health In Healthy Prepubescent Children

Abstract

A third of children in the United States (US) are considered to be overweight or obese. Obesity increases risk for cardiovascular disease, diabetes, cancer, and asthma. Asthma is the most common chronic childhood disease in the US. Recently, along with childhood obesity, the prevalence of childhood asthma has increased dramatically. Aerobic fitness reportedly offers protection against disease risk. To date, little is known about the role body composition and physical activity play in airway health in children. PURPOSE: To determine whether body composition and/or physical activity would impact airway health in healthy prepubescent children. METHODS: Pulmonary function tests (FEV1, FVC, FEF25-75) and exhaled nitric oxide (eNO; i.e., airway inflammation) were performed pre and post exercise in 40 healthy (20 boys, 20 girls), non-asthmatic prepubescent children (Tanner stage 1, 9.7 ± 0.8 yrs) with a wide range of physical activity habits. Physical activity was determined via questionnaire (BS-BAQ). Each subject completed an incremental exercise test to exhaustion (V02max) on a cycle ergometer. Body composition was determined via DEXA. Subjects were divided into groups by whether they met ACSM activity guidelines or not (active, inactive) and by body fat (high fat, >21.1%, low fat, <21.1%; 50th percentile for our subjects). RESULTS: The change in FEV1 (pre-post exercise) was inversely related (r=0.47, P<0.05) to % body fat; subjects with the highest body fat demonstrated the greatest decrease in FEV1 (i.e., airway constriction). Mean values for changes in FEV1 and eNO (pre-post exercise) were not significantly different between the active and inactive groups. The change in FEV1 (pre-post exercise) was related (r=0.41, P<0.05) to V02max; subjects with the lowest V02max had the greatest decrease in FEV1. The high fat inactive group had a significantly greater decrease in FEV1 post exercise (-11.0 ± 3%), compared to the high fat active (-7.1 + 2.3%), low fat inactive (-4.0 + 2.6%) and low fat active group (-1.3 + 1.5%). CONCLUSION: These results suggest that physical inactivity and high body fat negatively impact airway health in prepubescent children which may contribute to increased prevalence of asthma.