The Role Of BMI On Cognition Following Acute Physical Activity In Preadolescent Children

Abstract

PURPOSE: There is an increasing prevalence of physical inactivity during childhood, concurrent with a rise in obesity rates (as measured by Body Mass Index, BMI), which is associated with a variety of health problems. However, the extent to which increased BMI influences acute physical activity (PA) benefits on cognition in childhood remains unknown. The aim of this study was to examine the relationship of BMI and acute PA on performance of a modified flanker task, which modulates inhibitory control. METHODS: In a sample of 116 children pooled from four prior studies (ages 8-11; 51 females), demographic measures of age, sex, IQ, socioeconomic status, and aerobic fitness were considered along with BMI. Children participated in a counterbalanced, randomized crossover study, whereby they completed two different interventions; 20 minutes of restful reading or treadmill walking (60-70% heart rate max). Following each intervention, children performed a modified flanker task to assess inhibitory control. Correlations were conducted to determine the influence of demographic variables, fitness, and BMI on inhibitory control following each intervention. Subsequent hierarchical regression analyses were performed with significant demographic factors in the first step, aerobic fitness in the second step when significant, and BMI in the final step. RESULTS: Analyses indicated that children exhibited improved task performance (p’s ≤ 0.001) following the walking intervention, as well as decreased interference (p = 0.04), indicating greater benefits following acute PA for the task condition requiring greater inhibitory control. Regression analyses were conducted to examine the influence of BMI on task performance following each intervention. Results revealed that increased BMI was related to decreased performance following acute PA (p = 0.001), an effect not seen following restful reading (p’s ≥ 0.11). CONCLUSIONS: These findings indicate that the beneficial effects following an acute bout of PA on cognition are generalized across conditions of a flanker task, but are selectively greater for the task conditions requiring greater inhibitory control. However, the effects may be blunted in children with higher BMI. These results suggest that indices of inhibition are influenced by PA and adiposity in children.