Abstract
BACKGROUND: This cluster-randomized trial examined the effects of active breaks (AB) and physically active lessons (PAL) on cognitive function and health indicators in elementary school children. METHODS: Six schools were randomly assigned to three groups: AB group (n = 61), PAL group (n = 77), and a control group (CTL, n = 46). First-year elementary school students participated (6.9 ± 0.6 years; 52.7% girls), and the interventions lasted eight weeks. Cognitive function was measured via reaction time and correct responses on computerized tests (Go/NoGo, DigitSpan, Mental Rotation, Visual Search, and Cueing Posner). Secondary outcomes included physical activity, quality of life, daytime sleepiness, and school perception. RESULTS: Significant group-by-time interactions were found in four tests: Go/NoGo (reaction time: p = 0.045), DigitSpan (correct responses: p = 0.020), Mental Rotation (reaction time: p = 0.049), and Cueing Posner (reaction time: p = 0.017). Only the PAL group presented a reduction in reaction time in inhibitory control (Go/NoGo) (change from baseline [Δ] = -106.4 ms; p < 0.001; d = 0.50), with a greater reduction than the AB group (difference-in-differences [DiD] = -107.3 ms; p = 0.019; d = 0.47). Short-term memory (Digit Span) improved only in the PAL group (Δ = + 0.6; p < 0.001; d = 0.44), with larger gains than the CTL group (DiD = + 0.7; p = 0.024; d = 0.54) and AB group (DiD = + 0.7; p = 0.010; d = 0.49). Spatial reasoning (Mental Rotation) improved in both the PAL (Δ = -1967.5 ms; p < 0.001; d = 0.72) and AB groups (Δ = -1477.8 ms; p < 0.001; d = 0.54), but only the PAL group showed a greater change than the CTL group (DiD = -1394.0 ms; p = 0.012; d = 0.54). Spatial orientation (Posner Cueing) improved in all groups (PAL group: Δ = -386.6 ms; p < 0.001; d = 0.68; CTL group: Δ = -183.8 ms; p = 0.024; d = 0.29; AB group: Δ = -158.4 ms; p = 0.007; d = 0.36), with the PAL group presenting greater reductions than the CTL (DiD = -202.8 ms; p = 0.045; d = 0.33) and AB groups (DiD = -228.2 ms; p = 0.007; d = 0.45). CONCLUSIONS: Physically active lessons enhanced various cognitive functions, while active breaks, although less impactful, also represent a beneficial strategy. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (REBEC trial: RBR-10zxwdrh, retrospectively registered on 2025-01-09, https://ensaiosclinicos.gov.br/rg/RBR-10zxwdrh ).