Differences in Children’s Physical Activity During Outdoor and Indoor School Recess in Hot Weather

BACKGROUND: Outdoor recess during school is a prominent source of children's physical activity; however, children's movement is likely affected when recess is moved indoors due to inclement weather. This study assessed the amount and intensity of children's physical activity during school recess when it took place inside gyms or classrooms compared with traditional outdoor recess during periods of high heat. METHODS: This cross-sectional observational study included assessments of movement intensity levels during recess (sedentary, light, and moderate to vigorous physical activity [MVPA]) among fifth-grade children (N = 251; ages = 10-12 y) at 5 schools in the Phoenix Metropolitan Area (Arizona, United States) between August and September 2024. School personnel determined the locations for recess (in classrooms, gyms, or outdoors). Physical activity levels were assessed using the System for Observing Play and Leisure Activity in Youth during 91 observations across 15 recess periods. Differences in mean physical activity intensities were compared between recess locations for the entire sample and by child sex using 1-way analyses of variance. RESULTS: Outdoor temperatures ranged from 91 to 109 °F (33-43 °C). Most recess was held outside (60%), with 20% in classrooms and 20% in gyms. All physical activity intensities differed between locations, with the greatest difference in time occurring in MVPA in gyms (51%) and outdoors (28%) compared with classrooms (11%), where children were mainly sedentary (71%). Boys spent more time in MVPA and less time sedentary than girls across all settings. CONCLUSIONS: Having indoor facilities to support movement such as gyms provides more MVPA and less time sitting compared with classrooms or outdoors on high-heat days.