Lanza Kevin, Alcazar Melody, Durand Casey P, Salvo Deborah, Villa Umberto, Kohl Harold W
Department of Epidemiology, Human Genetics, & Environmental Sciences, School of Public Health in Austin, The University of Texas Health Science Center at Houston, Austin, TX,USA.
Parks and Recreation Department, Austin, TX,USA.
J Phys Act Health. 2022 Dec 23;20(2):134-141. doi: 10.1123/jpah.2022-0405. Print 2023 Feb 1.
Extreme heat may discourage physical activity of children while shade may provide thermal comfort. The authors determined the associations between ambient temperature, shade, and moderate to vigorous physical activity (MVPA) of children during school recess.
Children aged 8-10 (n = 213) wore accelerometers and global positioning system monitors during recess at 3 school parks in Austin, Texas (September-November 2019). Weather data originated from 10 sensors per park. The authors calculated shade from imagery using a geographic information system (GIS) and time-matched physical activity, location, temperature, and shade data. The authors specified piecewise multilevel regression to assess relations between average temperature and percentage of recess time in MVPA and shade.
Temperature ranged 11 °C to 35 °C. Each 1 °C higher temperature was associated with a 0.7 percentage point lower time spent in MVPA, until 33 °C (91 °F) when the association changed to a 1.5 lower time (P < .01). Each 1 °C higher temperature was associated with a 0.3 percentage point higher time spent under shade, until 33 °C when the association changed to a 3.4 higher time (P < .001). At 33 °C or above, the direct association between shade and MVPA weakened (P < .05), with no interaction effect above 33 °C (P > .05). Children at the park with the most tree canopy spent 6.0 percentage points more time in MVPA (P < .01).
Children engage in less MVPA and seek shade during extreme heat and engage in more MVPA in green schoolyards. With climate change, schools should consider interventions (eg, organizing shaded play, tree planting) to promote heat safe MVPA.
酷热天气可能会抑制儿童的身体活动，而阴凉处则可提供热舒适感。作者们确定了学校课间休息期间环境温度、阴凉处与儿童中等到剧烈身体活动（MVPA）之间的关联。
2019年9月至11月期间，在得克萨斯州奥斯汀市的3个学校公园，8至10岁的儿童（n = 213）在课间休息时佩戴了加速度计和全球定位系统监测器。气象数据来自每个公园的10个传感器。作者们使用地理信息系统（GIS）根据图像计算出阴凉处，并将身体活动、位置、温度和阴凉处数据进行时间匹配。作者们指定了分段多水平回归来评估平均温度与MVPA及阴凉处课间休息时间百分比之间的关系。
温度范围为11℃至35℃。温度每升高1℃，MVPA的时间就减少0.7个百分点，直到33℃（91°F）时，这种关联变为减少1.5个百分点（P < 0.01）。温度每升高1℃，在阴凉处的时间就增加0.3个百分点，直到33℃时，这种关联变为增加3.4个百分点（P < 0.001）。在33℃及以上时，阴凉处与MVPA之间的直接关联减弱（P < 0.05），在33℃以上没有交互作用（P > 0.05）。树冠最多的公园中的儿童在MVPA中的时间多6.0个百分点（P < 0.01）。
在酷热天气下，儿童进行的MVPA较少且会寻找阴凉处，而在绿色校园中进行的MVPA较多。随着气候变化，学校应考虑采取干预措施（如组织在阴凉处玩耍、植树）以促进热安全的MVPA。
