Abstract

Highlights: What are the main findings? Outdoor physical activity showed weak negative correlations with school-related stress in pre-adolescents aged 8, 10, and 12 years (r = ?0.02 to ?0.07), indicating a modest protective effect that strengthens with age. Positive correlations with school arguments (r = 0.03–0.08) were consistent across all age groups, suggesting increased social interactions may lead to minor conflicts. What is the implication of the main finding? School-based programs integrating outdoor physical activity, especially for older pre-adolescents, could reduce stress and support emotional resilience, with supervision to minimize peer conflicts and promote equitable well-being across diverse contexts. Background/Objectives: Subjective well-being (SWB) in pre-adolescents declines with age due to rising school-related stress and boredom. Outdoor physical activity (PA) may mitigate these effects, yet age-specific associations remain understudied. This study investigated age differences in relationships between outdoor PA and school emotional well-being (stress and arguments) using multinational data. Methods: Cross-sectional secondary analysis of the International Survey of Children’s Well-Being (ISCWeB) third wave (2017–2019) involved 128,184 pre-adolescents (mean age 10.24 years, SD 1.70; 49.56% boys) from 35 countries, stratified by age (8, 10, 12 years). Outdoor PA was assessed on a 0–6 frequency scale; stress and arguments on 0–10 scales, with 8-year-olds’ responses harmonized from 5-point emoticons. Descriptive statistics and stratified Spearman correlations were calculated (p < 0.05). Results: Outdoor PA peaked at age 10 (mean 3.17, SD 1.62), while stress varied with age (mean 3.99, SD 0.50 at 8 years; 4.20, SD 2.50 at 12 years). Very small associations emerged: Weak negative stress correlations (r = ?0.02 to ?0.07, p ? 0.045; r2 < 0.005) across ages, alongside positive argument associations (r = 0.03–0.08, p < 0.001). Conclusions: Outdoor PA modestly associates with lower stress in older pre-adolescents but may be associated with elevated peer conflicts. This dual effect adds nuance to interventions, highlighting supervision needs. Age-tailored, supervised school interventions could optimize emotional benefits during late pre-adolescence. © 2025 by the authors.