NAAEE

The outdoor areas of many schools consist of high amounts of impervious materials and few trees. These conditions result in high surface temperatures during the hotter months which may curtail children’s activity levels. The aim of this study was to evaluate how green features, such as trees, impact ambient temperatures and physical activity levels of children at school parks.

Three elementary schools in Austin, Texas, United States participated in this study. While the outdoor spaces used by the schools for recess had equivalent features (including playgrounds, multipurpose fields, running tracks, and basketball courts covered by artificial shade structures), they differed in the amount of tree canopy cover. Study participants (N=213) from the three schools wore accelerometers and global positioning system monitors while using the school parks during recess for 10 consecutive school days in September and 5 consecutive school days in November. Sensors in each of the school parks collected weather and shade measurements during the same recess periods.

An analysis of the data showed that children were relatively active during recess in the school parks. They spent about one half of the time engaged in light physical activity and about one third engaged in moderate to vigorous physical activity (MVPA). The children were not under shade about two-thirds of the time. However, with higher temperatures, children spent less time engaged in MVPA and more time under shade. Once temperatures reached 33 °C (91.4 ⁰F), children spent more time under shade than in MVPA. Children at the park with the most tree canopy spent more time in MVPA than children in the other parks.

This study “found a direct association between shade and MVPA that lessened as temperatures increased until 33 °C, after which children were more likely to spend time under shade and not engaging in MVPA.” These results highlight the need for schools to consider tree planting and other shaded play initiatives to promote heat safe MVPA.