Abstract

Highlights: What are the main findings? Good mental health partially mediates the link between an unhealthy lifestyle and executive functions. Low physical activity and high screen time were inversely related to attention, inhibition, cognitive flexibility, and working memory. What is the implication of the main finding? Promoting active lifestyles and mental well-being from early ages may enhance cognitive development. Schools and families are key in integrated actions for physical activity, mental health, and screen use. Background: Childhood and adolescence are increasingly recognized as life stages that pose specific challenges for treating and promoting mental health and cognitive development. Objective: The objective of the present study was to determine the potential mediating role of good mental health in the association between an unhealthy lifestyle (i.e., low physical activity (PA) and high screen time (ST)) with executive functions (EFs) (i.e., attention, inhibition, cognitive flexibility, and working memory) in children and adolescents. Methods: A cross-sectional investigation with 625 students aged 10–17 years participated. The Krece Plus questionnaire (lifestyle, PA, and ST), Depression Anxiety and Stress Scale (DASS-21, metal health), and CogniFit (EFs) were used in the present study. Results: Good mental health presented a partial mediating role in the relationship between a bad lifestyle and EFs. Likewise, a bad lifestyle was linked inversely to attention (? ?37.45, p = 0.002), the executive function of cognitive flexibility (? ?85.91, p < 0.001), inhibition (? ?60.16, p < 0.001), and working memory (? ?75.73, p < 0.001). Conclusions: Good mental health acts as a relevant mediator in child and adolescent cognitive development. These results reinforce the need to promote active and healthy lifestyles, as well as strategies that promote psychological wellbeing from an early age. Schools and families play an important role as protective agents and promoters of integral development; it is therefore recommended to implement intervention programmes that strategically address the physical activity, mental health, and digital habits of this population. © 2025 by the authors.