Accelerometer measured physical activity, methodological and health related aspects

Abstract: Introduction Ihe association of physical inactivity with mortality, cardiovascular disease and cancer is extensively studied in adults. Clustering of cardiovascular risk factors and objectively measured physical activity in children and youth has not been convincingly established. The sustainability of objectively measured physical activity into adulihood is not satisfactorily studied. Accelerometers are suitable for assessment of physical activity. However, due to constantly newer accelerometer-models on the market, studies should be performed to guarantee their interchangeability. Aims I. ls accelerometer measured physical activity correlated to a composite cardiovascular risk factor score in children? II. Are physical activity, aerobic fitness and body fat associated with autonomic function in children? III. Does physical activity track in children over a 2 year time period? IV. Is the new generation Actigraph accelerometer (GTIM) comparable to the old generation Actigraph accelerometer (7164) in laboratory settings? V. Does time spent in physical activity differ between Actigraph GTlM and 7164 in freeliving settings? Methods Parameters measured: aerobic fitness (VO2PEAK), body fat (by dual X-ray absolptiometry), heart rate, blood pressure, physical activity (accelerometers), head-up tilt test and deep breath test. Results and Conclusions I. Physical activity was correlated to a composite cardiovascular risk factor score. II. Low-moderate tracking of all physical activity levels was observed in 9-12 year otd children. III. Physical activity and body fat were not significantly associated with autonomic function. Aerobic fitness was correlated to autonomic function in boys. IV. Accelerometer GTIM showed lower counts compared to 7164 in laboratory settings. V. Time spent in physical activity was lower from accelerometer GTIM compared to 7164 in free-living settings.