Designing heat-resilient schoolyards to support active outdoor play

Introduction and aim

School recess plays a crucial role in promoting physical activity, contributing up to 44% of children’s physical activity during school days. Yet with rising global temperatures, extreme heat poses a growing barrier to outdoor activity in schoolyards.

Shade—whether from trees or structures—may help offset thermal discomfort, but its role in sustaining physical activity levels under hot conditions is an understudied topic.

To better understand these dynamics, Lanza and colleagues (2022) examined how ambient temperature and shade availability affect children’s moderate to vigorous physical activity (MVPA) in schoolyards.

The study, conducted at three elementary schools in Austin, Texas, examined MVPA and locations of 213 children aged 8-10. Accelerometers and GPS monitors were used during recess in the fall of 2019, with temperatures ranging from 11 °C to 35 °C (53-96 °F).

Findings from this study are especially relevant for school administrators, public health officials, and urban planners aiming to create heat-resilient environments that promote children’s health and well-being in a warming climate.

"Although climate-controlled indoor spaces can offer relief from heat, prioritising shaded outdoor play areas preserves children's vital access to nature and its crucial health benefits.

Temperature and MVPA

As temperatures increased, the time spent in MVPA decreased.
For every 1°C rise in temperature, children spent 0.7% less time in MVPA until temperatures reached 33°C.
After this point, the decrease in MVPA became more pronounced, with a 1.5% drop for each additional 1°C.

Temperature and Time in Shade

As temperatures rose, children spent more time in the shade.
For every 1°C increase, time spent in shade increased by 0.3% until reaching 33°C, after which the increase jumped to 3.4%.

Tree Canopy and MVPA

Schools with more green features and tree canopy saw a notable increase in MVPA.
Children in schoolyards with the most tree coverage spent 6% more time being active compared to those at schools with less greenery.

Shade and MVPA

There was a positive association between physical activity and shade up until 33°C, meaning children in shaded areas were more likely to engage in MVPA.
However, once temperatures exceeded 33°C, this effect weakened, with no significant interaction between shade and MVPA at temperatures above 33°C.

Key findings

During recess periods, which lasted an average of 23 minutes, children were relatively active: 48% of the time was spent in light physical activity, and 36% in MVPA. However, about 68% of the time, children were not under shade.

Visual key findings3

Disclaimer: Lanza and colleagues (2023) emphasize that the temperature threshold of 33°C, where the relationship between temperature, shade, and MVPA significantly changed, may not apply universally. Children in Austin, Texas, may have a higher heat tolerance due to acclimatization, whereas other studies suggest that temperatures above 20°C (68°F) can already pose risks to children’s physical activity levels, especially in cooler climate areas.

Recommendations to promote heat-resilient schoolyards

Schoolyard design:

Install shade structures, both artificial and natural, over playgrounds, basketball courts, and rest areas to create thermally comfortable spaces for outdoor play.
Increase tree canopy coverage to lower playground temperatures and promote higher levels of MVPA. Prioritize tree planting in low-income communities and protect mature trees, which provide greater cooling and health benefits, compared to smaller ones.
Match shade type to space function and use artificial structures over active sports fields to avoid obstructing play, and plant trees around rest areas and playground edges

Recess guidelines:

Schedule recess during cooler times of the day and develop formal procedures to adjust (not cancel) outdoor play during extreme heat.
Update hot weather guidelines to encourage use of shaded areas when temperatures reach or exceed 33 °C, with organized activities directed to thermally comfortable spaces.

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