A prospective examination of children's time spent outdoors, objectively measured physical activity and overweight

Cleland, V., Crawford, D., Baur, L. A., Hume, C., Timperio, A., & Salmon, J. (2008). A prospective examination of children’s time spent outdoors, objectively measured physical activity and overweight. International Journal of Obesity, 32(11), 9. http://dx.doi.org/10.1038/ijo.2008.171

Older children who spend more time outside tend to be more physically active and are less likely to be overweightCleland and colleagues investigated whether the amount of time children spend outdoors is related to their physical activity levels and being overweight.

About 200 five- to six-year-old and 350 ten- to twelve-year-old children from 19 randomly selected elementary schools in Melbourne, Australia participated in this study. In 2001 and 2004, parents reported the amount of time their children spent outdoors and researchers recorded children's physical activity levels using an accelerometer and measured children's weight and height.

In their paper, Cleland and colleagues report many findings, some of which are discussed below. The researchers found, for example, that children spent significantly more time outdoors during warmer months as compared to cooler months; boys had significantly higher levels of moderate and vigorous physical activity (MVPA) on weekdays than girls; the prevalence of overweight increased significantly between 2001 and 2004 for both younger and older children, as well as boys and girls; and among the older children, boys generally spent significantly more time outside than girls. Cleland and colleagues also found that older children who spent more time outside were generally more physically active and had a lower prevalence of overweight than children who spent less time outside. For example, the researchers found that each additional hour older girls spent outside during the cooler months was associated with an extra 26.5 minutes per week of MVPA and that each additional hour older boys spent outside during the cooler months was associated with an extra 21 minutes of MVPA. When examining changes over the three-year period, Cleland and colleagues found that the more time older girls and boys spent outside on weekends at baseline (2001), the higher their MVPA on weekends at follow-up (2004). In addition, the researchers found that in 2004, the prevalence of overweight among older children was 27-41% lower for those children who spent more time outside in 2001. With regard to younger children, Cleland and colleagues found few associations between time spent outdoors, physical activity, and overweight.

The results of this study suggest that encouraging 10- to 12-year-old children to spend more time outdoors may help increase physical activity levels and reduce the prevalence of overweight.

The Bottom Line

Older children who spend more time outside tend to be more physically active and are less likely to be overweight