Poster #38 - Extreme heat and physical activity of preschoolers during self-directed outdoor play

• In Event: Poster Session 07

Abstract

Young children are currently not reaching recommended levels of physical activity for health and well-being. In warm climates, ambient temperatures may serve as a barrier to children engaging in physical activity due to thermal discomfort. High temperatures are associated with lower physical activity levels of adults (Obradovich & Fowler, 2017), yet no studies have focused on the temperature-physical activity relationship for young children in warmer climates (Zheng et al., 2021). The purpose of this study is to determine the association between hourly temperature and physical activity of preschoolers during outdoor play at an early care and education (ECE) center.

During two weeks in April 2022 wherein air temperature ranged 72°F–95°F (22–35°C), the activity of 47 preschool-aged children was objectively measured via waist-worn ActiGraph GT3XP-BTLE devices (ActiGraph, Pensacola, FL, USA) for four consecutive days (N=168 person-days) during child-initiated play in the outdoor learning environment of an ECE center in Austin, Texas, USA. Hourly observations of outdoor air temperature, relative humidity, and precipitation originated from a weather station (30.3208°, −97.7604°; station ID: USW00013958) of the Global Historical Climatology Network installed near the study site. Climatological data were matched to the time logs of outdoor play. During data collection, neither precipitation nor an air quality alert was observed. Established cut-points (Pate et al., 2006) were used to categorize the percentage of time each child was sedentary and the percentage of time they engaged in moderate to vigorous physical activity (MVPA). To examine how air temperature may predict the percentage of time children were sedentary or engaged in MVPA while outdoors, we used multi-level regression models, controlling for relative humidity and accounting for nesting of observations (N=168) within children (N=47).

All children attended the same ECE center in which >90% of families earned >$100,000/year. Participants were on average 4.5 years old (SD=0.5), 60% male, and 57% non-Hispanic white. Across the range of temperatures observed (72–95°F), children’s physical activity was negatively impacted by higher temperatures (Figure 1). On warmer days, children spent more time sedentary, b = 0.47, SE = 0.09, p < .001, 95% CI [.30, .64], β = 0.39, and less time in moderate to vigorous physical activity during outdoor play, b = -0.34, SE = 0.08, p < .001, 95% CI [-.49, -.20], β = -0.34. The model estimates that at 72°F (22°C), children were sedentary for 62% of outdoor play, on average, compared to 72% at 95°F (35°C). Similarly, at 72°F, children were in MVPA 27% of outdoor play compared to 19% at 95°F.

As temperatures increased from 72°F to 95°F during outdoor play at an ECE center, preschool-aged children were more sedentary and engaged in less MVPA. This study suggests that extreme heat may decrease physical activity levels of young children. Given the projected rise in extreme heat days due to climate change, future studies should examine the temperature-physical activity relationship for young children from low-income communities and communities of color, and design and evaluate ways ECE providers can mitigate the effects of heat on activity.

Authors

• Andrew E. Koepp, University of Texas at Austin

• Courtney Byrd-Williams, University of Texas Health Science Center at Houston
  Presenting Author

• Kevin Lanza, University of Texas Health Science Center at Houston

• Amy Bryan, University of Texas at Austin

• Elizabeth T. Gershoff, University of Texas at Austin