[Physical activity in asthmatic children: use of an accelerometer]

Physical activity is thought to be important not only for healthy children but also for asthmatic children from medical point of view. Some epidemiological studies revealed positive association between asthmatics and overweight (obesity). In order to verify the decreased physical activity in asthmatic children, a comparative study to measure objective physical activity is needed. We measured daily steps of asthmatic children by using accelerometers and evaluated the difference between the steps of asthmatic children and healthy controls.

Fifty seven asthmatic children from the fourth to the sixth grade of Japanese elementary school agreed to join this study in our allergic outpatients units and used pedometers with the exercise intensity measurement function (OMRON HJ151) during 2 weeks. We measured their physical activity by using daily average steps and exercise steps during moderate to severe exercise, and evaluated weekday activity and holiday activity. These data were analyzed by comparing with those of age and weight matched controls.

We obtained answers from 39 asthmatic children. Compared with health male controls, weekday average steps, weekday average exercise steps, and holiday average exercise steps of male asthmatic children was fewer, respectively (p = 0.003, p < 0.001, p = 0.037).

Asthmatic children who receive treatment in the allergic outpatients units, especially boys, engaged in lower steps than healthy ones. This result suggests that asthma may cause decreased physical activity in children.