The mediating role of physical fitness in the relationship between 24-h movement guidelines and arithmetic fluency in adolescents: the MOVESCHOOL study

The clustering of unhealthy movement behaviours is highly prevalent among adolescents and significantly impacts both health and academic outcomes. While evidence linking 24-hour Movement Guidelines to general academic outcomes is substantial, research specifically on arithmetic fluency remains limited. This cross-sectional study analysed 578 Spanish adolescents (aged 11–15 years) to quantify compliance with physical activity, screen time, and sleep recommendations and to explore the role of physical fitness in this relationship. Results revealed alarmingly low adherence: only 1% of adolescents meet all three health recommendations, while nearly half meet none. Results demonstrate a threshold effect, showing that adolescents who follow at least two guidelines achieve modest but significant higher scores in arithmetic fluency (B = 7.81, η²_p = .015, p = .005). Notably, this academic advantage is statistically accounted for by higher levels of cardiorespiratory fitness, which is consistent with a mediating role in all comparisons (B from 0.88 to 2.43; all 95% CI exclude zero), whereas muscular fitness does not. Findings suggest promoting combined healthy habits may be more effective for cognitive development than targeting single behaviours. Integrating movement-based strategies into school environments could enhance potentially arithmetic fluency success by fostering the cardiorespiratory health necessary for optimal arithmetic learning.