Study of Exercise and Cognition in Overweight Children 1A Study of the Effects of Aerobic Exercise on the Executive Cognitive Functioning of Overweight ChildrenAnne KimballUniversity of GeorgiaFebruary 27, 2009Study of Exercise and Cognition in Overweight Children 2AbstractEvidence suggests that exercise can have a variety of beneficial effects on cognition. This study investigates whether exercise benefits children’s executive control (EC). EC constitutes supervisory control of cognitive functions, including inhibition and allocation of attention and memory. The participants were 25 sedentary, overweight (BMI ≥ 85th percentile) children ages 8 – 11 years old. Subjects were randomly placed into either an attention control group, which engaged in instructor-led sedentary activities, or an exercise intervention group, which participated in aerobic training for 40 minutes/day, 5 days/week for 4 months. Subjects were tested at the beginning and at 9 weeks into the intervention using behavioral measures of EC. These measures included a) an antisaccade task that involves the inhibition of a prepotent visual response to a cue and the generation of eye movement towards the mirror-image of that cue, and b) an Eriksen flanker task which requires selective attention to a central target and suppression of interfering responses presented in the periphery. Because antisaccade and flanker tasks are relatively well-understood measurements of EC, evaluating changes in task performance over time could provide evidence for an exercise effect on cognition. It is hypothesized that the exercise group will demonstrate increased performance on both antisaccade and flanker tasks as compared to the control group. By providing evidence for the positive effects of exercise on cognition, this study would support the implementation of aerobic exercise programs in schools so that American schoolchildren will be healthier, both physically and mentally.Study of Exercise and Cognition in Overweight Children 3IntroductionAccording to the World Health Organization, obesity is one of the most important public health issues, and excess body weight is the sixth most important risk factor contributing to disease worldwide, with about 110 million children now classified as overweight or obese (Cali & Caprio, 2008). Pediatric obesity is an epidemic, and its prevalence is increasing rapidly (Strauss & Pollack, 2001). In the state of Georgia, 61% of children between the ages of 6-11 are overweight, with a Body Mass Index at or above the 85th percentile (Davis et al., 2005). Childhood obesity correlates with many health concerns, including lower performance in IQ tests (Li, 1995) and poor academic achievement (Taras & Potts-Datema, 2005). Experimental evidence has shown that exercise enhances children’s mental functioning in ways that are central to cognitive development (Davis et al., 2007).The current research is designed to evaluate whether aerobic exercise benefits executive cognitive control in overweight children. Executive control (EC) refers to the supervisory control of cognitive functions, including goal-setting, self-monitoring, use of strategies, inhibition, and allocation of attention and memory (Eslinger, 1996). EC is crucial for child development, cognitive development, and adaptive behavior (Lyon et al. 1996). Measures of EC have also been positively related to achievement (St. Clair-Thomson, 2006).In this study, sedentary, inactive, and overweight children were placed in either an exercise intervention group or an attention control group. Both groups were tested onStudy of Exercise and Cognition in Overweight Children 4two behavioral measures of EC in a pre-test and after 9 weeks of the study. The two measures of EC are the antisaccade and flanker tasks.Antisaccade tasks provide a direct and simple measure of inhibition. During the task, a participant fixates on a central target. This target is then turned off and a peripheral cue is turned on. Participants are instructed not to look at the cue but to look at the opposite side, the same distance from the center. An initial glance towards the cue is an error and is construed as a failure of inhibition. Performance on this task (measured as percent correct responses and reaction time of correct saccades) may be a good indicator of potential exercise-related changes in neural circuitry. Antisaccade error rates are generally stable between multiple measurements in time in adults (Ettinger, 2003); however, performance can be improved by daily purposeful practice (Dyckman, 2005 and Fischer, 2000). Thus, while antisaccade performance in adults is generally stable, performance can change with intervention (practice). This inhibitory process is malleable, and thus may respond to exercise.Flanker tasks provide measures of selective attention and inhibition. Correct performance in the flanker task requires selective attention to a middle stimulus (that conveys information about the correct response) and ignoring adjacent stimuli that are either congruent (e.g. > > > > >) or incongruent (e.g. < > < < >) in nature. Across numerous versions of flanker tasks, correct reaction times are longer in the incongruent condition (Colcombe, 2004 and Eriksen, 1974), suggesting that subjects experience increased conflict compared with the congruent condition. Evidence has shown the beneficial impacts of exercise on physical, mental, and cognitive health. Hillman et al. (2008) examined the benefits of aerobic physical activityStudy of Exercise and Cognition in Overweight Children 5for cognition and brain function on molecular, cellular, systems, and behavioral levels. A link has been demonstrated between physical activity and reduced cardiovascular disease, colon and breast cancer, obesity, depression, and anxiety. In addition, physical activity is linked to higher scores on cognitive functioning assessments, especially on executive control tasks. While physical activity is shown to be beneficial at all stages of life, this activity during childhood may help to improve and maintain cognitive health and functioning throughout the adult lifespan (Hillman et al., 2008). Past studies also have shown the beneficial effects of exercise programs on various aspects of cognition in adult populations. One study found that exercise training resulted in improvements in cognitive functioning in elderly adults with dementia and cognitive impairments, highlighting the role of