Self-reported physical activity is associated with cognitive function in lean, but not obese individuals

Convergent evidence demonstrates that greater physical activity is associated with better cognitive functioning across many patient and healthy samples. However, this relationship has not been well examined among obese individuals and remains unclear. The present study examined the relationship between performance-based measures of attention/executive function and self-reported physical activity, as measured by the International Physical Activity Questionnaire, among lean (n = 36) and obese (n = 36) college students. Lean individuals performed better than obese individuals on measures of attention/executive function. No significant differences in self-reported physical activity emerged between weight groups. Higher self-reported physical activity was related to faster reaction time in lean individuals but slower reaction time in obese individuals. Additionally, in lean individuals, higher levels of self-reported physical activity were related to more errors on a task of speeded inhibitory control. The results are consistent with previous research demonstrating that greater physical activity is associated with faster attention and executive function abilities in healthy samples and highlight the importance of examining reaction time and accuracy indices separately on these measures. The lack of association among obese individuals may be due in part to inaccurate self-report in the current study. Additionally, the cognitive consequences of obesity may outweigh the benefits of physical activity in this group. Future work should investigate these associations in obese individuals using physical activity interventions, as well as a combination of self-report and objective measures to investigate discrepancies in reporting.