No effects of a long-term physical activity intervention on executive functioning among adolescents

Objectives: We investigated whether a school-based physical activity intervention would lead to improvements in working memory, inhibition and cognitive flexibility in adolescents aged 13-15 years. Methods: The adolescents at the active school (n = 108) participated in an intervention that included increased physical activity for 20 min/day, focused on aerobic activity with low cognitive demands for an entire school year. The adolescents at the control school (n = 59) received no extra physical activity. At the beginning (baseline) and end (follow-up) of the school year, the participants performed tests of executive function (working memory, inhibition and cognitive flexibility) and performed tests of physical fitness and health. Results: There was no change in executive functioning at follow-up when comparing the schools. However, only 46% complied with the intervention. When non-compliers were excluded from the analyses, the results remained the same, except for a small but significant increase in working memory for the active school as compared to the control school. Conclusion: These results indicate that compliance with the intervention was low and that aerobic exercise with low cognitive load does not produce improvements in executive functioning.