Classroom Active Breaks Effects on Attention and Concentration Performance Among Adolescents Attending Upper Secondary Schools in Southern Italy

Background: Physical inactivity and prolonged sedentary behavior have been associated with impaired cognitive function during adolescence. Although classroom-based active breaks (ABs) have shown promising effects in primary school children, evidence among adolescents attending upper secondary schools remains limited. This study evaluated the effects of a four-month classroom-based ABs program on attention and concentration performance and explored whether selected participant and lifestyle-related characteristics moderated the intervention response. Methods: In this cluster-randomized controlled trial, 529 adolescents (302 females, 227 males; 14.3 ± 0.9 years) from 39 classes attending four upper secondary schools in Southern Italy were included. Classes were randomly allocated to the intervention group (IG; 20 classes, n = 288) or control group (CG; 19 classes, n = 241). The IG participated in two daily 10 min classroom-based ABs for four months, whereas the CG followed the usual school routine. At baseline, anthropometric characteristics, sport participation, sleep duration, daily smartphone use, adherence to the Mediterranean Diet, and concentration performance (CP score), assessed by the d2-R Test of Attention, were evaluated; only CP was reassessed after the intervention. Results: The primary mixed-effects model showed significantly higher adjusted post-intervention CP in the IG than in the CG (adjusted between-group difference = 56.7 points, 95% CI 21.7–91.6; p = 0.003). The intervention effect remained significant in a fully adjusted model including sex, organized sport participation, sleep duration, smartphone use, and Mediterranean Diet adherence (p = 0.004). Exploratory moderator analyses provided no evidence that the intervention effect differed according to any of these characteristics after correction for multiple testing. Conclusions: A four-month classroom-based ABs program can improve concentration performance among adolescents. High intervention fidelity and student attendance support the feasibility of implementing structured ABs within the school setting over the intervention period. Further research is needed to determine the long-term effects and implementation of ABs program in secondary schools.