Reviewed by Alicia Groce, OD: Pediatrics and Binocular Vision Resident Nova Southeastern University College of Optometry
In childhood, the brain is developing and undergoing changes that lay the foundation for cognition. Inactivity has been shown to be adversely linked to cognition. With children leading more sedentary lifestyles than in the past, inactivity is becoming a public health issue. Children sit at a desk all day at school and then go home and sit in front of the TV or computer and have mountains of homework instead of playing outside. Could sitting around all day be detrimental to your child’s brain and cognition? In this randomized controlled trial, the effect of physical activity on behavioral performance, attention and cognitive processing speed was explored.
Two hundred and twenty one children, aged seven to nine years old, participated in this study and were randomly assigned to either a physical activity program or a control group. All of the children were initially assessed for aerobic fitness, body mass index (BMI), IQ and pubertal timing with no significant differences found between the two groups. The children underwent pre-testing before the study to determine baseline aerobic fitness levels, response accuracy and reaction time to attentional inhibition tasks and cognitive flexibility tasks, attention allocation ( EEG P3 amplitude), and cognitive processing speed (EEG P3 latency). Attentional inhibition and cognitive flexibility are measures of executive function used in psychology. Attentional inhibition was measured by administering a modified flanker task in which the patient had to respond to congruent and incongruent arrays to test inhibition. Cognitive flexibility was measured by a switch task which tests the ability to shift attention and adapt to different situations. The participants assigned to the physical activity program received 30-40 minutes of physical activity and 45-55 minutes of games every day after school for nine months with an average attendance rate of 80.6%. The participants assigned to the control group underwent normal afterschool activities for nine months. Both groups underwent post-testing after nine months. Results are presented below as 95% confidence intervals.
Participants in the treatment group showed improved aerobic fitness compared to the control group (d=0.36). Attentional inhibition improved more in the treatment group as shown by response accuracy (d=0.27), attention allocation (P3 latency) (d=0.34), and cognitive processing speed (P3 amplitude) (d=0.31). Cognitive flexibility also showed greater improvement in the treatment group as shown by response accuracy (d=0.35) and attention allocation (d=0.27), but there was no change in cognitive flexibility between the two groups. The treatment group showed more improvement on all outcome measures compared to the control group.
This study shows that there is a link between increased physical activity and improved behavioral performance, attention, executive function, and cognitive processing speed. Thus, increased physical activity could translate into better attention and performance in scholastic activities. Inactivity first became a public health issue when it was linked to obesity, and now this study shows it is also linked to impaired attention, cognitive processing, and executive function. The increase of inactivity in children and its link to slower processing and executive function could be related to the increase in information processing disorders, learning disabilities, and ADHD in children. The results from this study serve as a good argument for increased physical activity in school and afterschool to promote brain development and flexibility.