Aerobic exercise enhances executive function and academic achievement in sedentary, overweight children aged 7-11 years.

unlabelledSummary of: Davis CL et al (2011) Exercise improves executive function and achievement and alters brain activation in overweight children: a randomized controlled trial. Health Pscyh 30: 91-98. [Prepared by Nora Shields, CAP Editor.] QUESTION: Does aerobic exercise improve cognition and academic achievement in overweight children aged 7-11 years?

designRandomised, controlled trial with concealed allocation and blinded outcome assessment.

settingAfter school program in the United States.

participantsOverweight, inactive children aged 7-11 years with no medical contraindication to exercise. Randomisation of 171 participants allocated 56 to a high dose exercise group, 55 to a low dose exercise group, and 60 to a control group.

interventionsBoth exercise groups were transported to an after school exercise program each school day and participated in aerobic activities including running games, jump rope, and modified basketball and soccer. The emphasis was on intensity, enjoyment, and safety, not competition or skill enhancement. The student-instructor ratio was 9:1. Heart rate monitors were used to observe the exercise intensity. Points were awarded for maintaining an average of>150 beats per minute and could be redeemed for weekly prizes. The high dose exercise group received 40 min/day aerobic exercise and the low dose exercise group received 20 min/day aerobic exercise and 20 min/day unsupervised sedentary activities including board games, drawing, and card games. The average duration of the program was 13 ± 1.6 weeks. The control group did not receive any after school program or transportation. OUTCOME MEASURES: The primary outcome was the Cognitive Assessment System taken at baseline and postintervention. This measure tests four cognitive processes: planning (or executive function), attention, simultaneous, and successive tasks with each process yielding a standard score with a mean of 100 and a SD of 15. Secondary outcome measures were the broad reading and mathematics clusters of the Woodcock-Johnson Tests of Achievement III.

results164 participants completed the study. At the end of the intervention period, there was a dose-response benefit of exercise on executive function (linear trend p=0.013) and mathematics achievement (linear trend p=0.045); ie, the post-intervention group scores for these outcomes increased with the intensity of exercise. Compared to the control group, exposure to either exercise program resulted in higher executive function scores (mean difference=-2.8, 95% CI -5.3 to -0.2 points) but not in higher mathematics achievement scores. The groups did not differ significantly on any of the other outcomes. There were no differences between the two exercise groups.

conclusionAerobic exercise enhances executive function in overweight children. Executive function develops in childhood and is important for adaptive behaviour and cognitive development.