Outdoor learning in urban schools: Effects on 4–5 year old children's noise and physiological stress

Natural outdoor environments reduce physiological stress. But in an urban school context, does outdoor learning still have beneficial effects even where nature exposure is more limited? The current, pre-registered study used wearable devices including heart rate monitors and actigraphs to examine physiological stress in 4–5 year old children across 8 matched indoor and outdoor sessions (N = 76 children, N = 601 sessions in total). Results revealed that children's resting heart rates while seated and listening to a teacher were significantly lower when outside compared to indoors (p < 0.001, d = 0.512). Children also moved more while seated during indoor sessions (p < 0.001, d = 0.546). Despite activities and resources being matched across conditions, outdoor learning sessions were significantly quieter than indoor ones, both when children were seated, listening to a teacher (p = 0.004, d = −0.455) and when actively engaged in play and learning activities (p < 0.001, d = 1.064). There was a significant positive correlation between noise levels and resting heart rate in the indoor condition (r(97) = 0.364, p < 0.001) but not in the outdoor condition. These findings suggest that learning outdoors, even in urban settings, associates with lower physiological stress in children and that this effect may partly be due to reduced noise. The fact that noise associates with resting heart rate indoors but not outdoors may indicate that being outside buffers children against the stressful effects of excess noise.