PHYSICAL ACTIVITY AND PULMONARY FUNCTION IN 9-18 YEAR OLD YOUTH.

841 The relationship between indicators of habitual physical activity and pulmonary function was considered in 254 boys and 231 girls 9-18 years of age from Phase I of the Quebec Family Study. Subjects were divided into three age groups, 9-12, 13-15, and 16-18 years. Indicators of habitual physical activity included estimated daily energy expenditure (EE) and time spent in moderate-to-vigorous (MVPA, median MET ≥ 4.8) and vigorous physical activity (VPA, median MET ≥ 6.0). Pulmonary function variables included peak expiratory flow rate (PEFR), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory volume in 2 seconds(FEV2), residual volume (RV), FEV1/FVC (FEV1%) and FEV2/FVC (FEV2%). Relationships were examined with partial correlation controlling for age and body size, and ANCOVA comparing differences between the extremes of EE, MVPA, and VPA. When age and height were statistically controlled, relationships between habitual physical activity and pulmonary function variables were generally low and non-significant (r<0.22), with the exception of FEV1% and FEV2% in 9-12 and 16-18 year old girls (-0.23<r<-0.51). Pulmonary function of subjects in the highest (more active) and lowest (least active) quartiles of the three indicators of habitual physical activity were also compared. Only FEV1% and FEV2% differed in 16-18 year old boys with greater values (1-3%) in the least active group. Other significant differences of pulmonary function between the highest and lowest quartiles of activity were inconsistent. The results thus indicate that lung volumes, capacities and flow rates are not related to estimated habitual physical activity in a general population of 9-18 year old youth.