Aerobic Exercise Training Improves Overweight Children’s Behavior in the Classroom Catherine L. Davis, Ph.D.1 Joseph Tkacz, M.S.1 Mathew Gregoski, M.S.2 Colleen Boyle, M.S.1 Catrina Creech, B.A.1 Phillip Tomporowski, Ph.D. 2 1Georgia Prevention Institute Department of Pediatrics Medical College of Georgia 2University of Georgia Department of Kinesiology

Childhood Obesity Childhood obesity is an epidemic with major implications (Strauss et al., 2001) Inactivity is a major contributor Overweight children are at risk for poor academic achievement (Dwyer et al., 2001; California Department of Education, 2005) However, the mechanism is unknown.

Exercise & Cognition: EXECUTIVE FUNCTION Meta-analysis indicates that physical activity improves executive function in older adults. (Colcombe & Kramer, 2003) Meta-analysis supports a similar effect of exercise on executive function in children. (Sibley & Etnier, 2003)

Classroom Behavior reflects Executive Function The Conners Teacher Rating Scale was selected as a behavioral index of executive function that is relevant to educational outcomes. Barkley conceptualizes attention-deficit disorder as a developmental delay in executive functions (Barkley, 1997) behavioral inhibition self-regulation of arousal working memory

Physical Activity and Classroom Behavior Adverse effects of physical activity on children’s classroom behavior have not been demonstrated that it would fatigue children or hyperstimulate them A study examining the impact of recess on classroom behaviors revealed that children worked more on task and fidgeted less on days they were offered a recess period (Jarrett et al., 2001)

Purpose of Study Hypothesis To test the hypothesis that physical activity may improve overweight children’s behavior in the classroom Children assigned to an exercise program will improve in classroom behavior relative to controls Exercise > controls Hypothesis

Methods Sample consisted of 123 healthy but overweight, sedentary children (Table 1) Recruited from local elementary schools in the Augusta area Age range 7-11 yrs BMI Percentile >= 85 Excluded data for subjects who did not attend posttest Included children on ADHD medication (n = 8)

RANDOM ASSIGNMENT Baseline Testing $100 Savings Bond for subjects who complete pretest (blood tests etc.) RANDOM ASSIGNMENT Lifestyle class only Exercise program (20 or 40min/d) Post-Testing $400 Savings Bond for subjects who complete posttest

Table 1. Sample Characteristics Control Condition Exercise Condition n 42 81 Age (years) 9.5 ± 1.1 9.3 ± 1.0 BMI Z-Score 2.1 ± 0.4 BMI %ile 98 ± 3 Boys Girls 31% 69% 48% 52% Whites Blacks 40% 60% 41% 59%

After School Exercise Program Every day after school for 10-15 weeks 20-40 min of aerobic exercise per day Transportation provided (school bus) Vigorous aerobic activities (running games, jump rope, basketball) (Gutin et al., 1999) Competition, skill deemphasized Incentives for goal achievement: Attend at least 4 days/week Average daily heart rate > 150 bpm Approximately 1 staff member per 9 children

Teacher Rating Scale Conners Teacher Rating Scales-Revised Short (CTRS:RS) is a 28 item report of ADHD and related conduct problems in the classroom (Conners, 1997) T-scores normed by age and sex Good reliability (Tables 2 & 3 from manual) Yields 4 discrete scales Oppositional: high scorers likely to break rules, have trouble with authority, and are easily angered Cognitive Problems/Inattention: high scorers tend to have trouble concentrating, learn more slowly, and have difficulty completing schoolwork Hyperactivity: high scorers have difficulty sitting still or remaining on the same task for very long; are very restless and impulsive ADHD: used to screen children for ADHD

Conners Sample Items Oppositional Scale A Little True Pretty Much True Not True Very True Oppositional Scale 2. Defiant………………………………………………... 0 1 2 3 10. Spiteful or vindictive…………………………….. 0 1 2 3 Cognitive Problems/Inattention Scale 14. Short attention span…………………………….... 0 1 2 3 23. Interrupts or intrudes others……………………. 0 1 2 3 Hyperactivity Scale 18. Lacks interest in schoolwork…………………… 0 1 2 3 27. Excitable, impulsive…………………………….... 0 1 2 3 ADHD Scale 5. Disturbs other children……………………….…… 0 1 2 3 17. Has difficulty waiting turn……………………….. 0 1 2 3

Oppositional Defiance Oppositional Defiance Conners Reliability (Conners, 1997) Table 2. Cronbach’s α Oppositional Defiance Cognitive Problems Hyper-Activity ADHD Index 6-8 yrs. Males Females .87 .88 .92 .95 .96 .94 9-11 yrs. .89 Table 3. Test-retest reliability Oppositional Defiance Cognitive Problems Hyper-Activity ADHD Index rxx .84 .92 .72 .80

Results ANCOVA tested the effect of exercise on Conners scales, adjusted for pretest scores. A planned contrast showed that children in the exercise conditions had lower adjusted posttest scores on the Cognitive Problems/Inattention scale (Adjusted Mean = 51.8, SE = 0.7) vs. controls (Adjusted Mean = 54.6, SE = 0.9; p < .05). Excluding children on ADHD meds did not affect results (p < .05). No significant effects of exercise were found on other Conners scales.

Scales ____________________________ Table 4. Exercise vs. control means (SD) on Conners Conners Exercise Scales ____________________________ Pre Post Diff. Oppositional 52.6 (11.0) 53.6(11.3) 1.1 (7.7) Cog. Problems 53.3 (11.2) 52.1(9.9) -1.2 (6.0) Hyperactivity 52.6 (9.9) 53.2(10.1) 0.6 (7.4) ADHD Index 54.9 (12.8) 54.4(12.1) -0.5 (7.7)

______________________________ Teacher Rating Scales at pre, post, and changes Control ANCOVA ______________________________ Pre Post Diff. Sig. 50.7 (7.3) 53.5 (10.0) 2.8 (10.4) p = .296 52.5 (10.0) 54.2 (12.1) 1.7 (7.0) p = .019* 51.0 (8.5) 52.0 (8.3) 1.0 (9.1) p = .765 53.4 (10.8) 55.7 (11.6) 2.4 (9.9) p = .078

Changes (SD) on Conners Scales p < .05 Cognitive Problems Hyper-activity ADHD Index Opposition

Discussion Exercise program caused greater improvements in classroom behavior in comparison to controls, who worsened This effect was specific to the Cognitive Problems/Inattention scale of the Conners Teacher Rating Scale This is consistent with an exercise effect improving executive function

Limitations Data collection is not yet completed. Teachers may have been aware of which group children were randomized to, therefore we cannot rule out bias. Comparison with a no-exercise control condition does not rule out possible effects of enrollment in a quality after-school program. Attention from staff, removal from TV and similar mind-numbing pursuits may have an effect.

Possible Mechanisms 6 mo of aerobic training (walking 3x/wk) in sedentary older adults vs. controls led to changes in brain activation in frontal lobes corresponding to improvements on tests of executive function. (Colcombe et al., 2004) The executive control and altering networks of the brain are rich in dopamine receptors, and are believed to be involved in the inattention aspect of ADHD (Swanson et al., 2000; see Dishman et al., 2006) Physical activity enhances brain dopamine synthesis (Sutoo et al., 1996), which can affect brain function and influence behavior

Public Health Implications Regular, aerobic exercise may be an effective way of improving the classroom behavior of overweight, sedentary children. Exercise is simple, inexpensive, and promotes general good health. Physical activity during and after school (PE, recess, etc) might promote academic achievement.

NIH Funding This study was supported by grants: R01 DK60692 & R01 DK70922 (Davis)