Improved frontoparietal white matter integrity in overweight children is associated with attendance at an after-school exercise program

Sport Experience and Physical Activity: Event-Related Brain Potential and Task Performance Indices of Attention in Young Adults

A growing body of literature demonstrates that engaging in sport regularly and maintaining an active lifestyle have a positive impact on cognition. The purpose of this study was to examine the influence of sport experiences and physical activity on attention, and explore whether the type of sport can impact differently on the neuroelectric system using Event-Related Potentials (ERPs). Thirty-three young adults (mean age = 19.72 ± 1.25) were divided according to their sport experience into swimmers, karateka, and irregular exercisers. Participants performed auditory oddball tasks, while measures of task performance and ERPs were collected. The results indicated that exercisers, regardless of their sport experience, exhibited a larger and shorter P3 compared to irregular exercisers. However, no significant difference was observed in the reaction time (RT) between groups. No statistically significant differences in the RT and P3 were present between swimmers and karateka. These findings suggest that sport experiences, regardless of the type, are associated with a larger amount of neural attentional resources and faster stimulus evaluation speed. The results replicate previous studies that have reported improved cognitive functions in more active individuals. They further extended the current knowledge by indicating that both swimming and karate influence attention and do not differentially alter the brain response.

Cardiorespiratory fitness as a mediator of the relationship between birth weight and cognition in school children

Objectives: To examine differences in cognition parameters by birth weight categories and to analyze whether the relationships between birth weight and cognitive functions are mediated by cardiorespiratory fitness (CRF) in schoolchildren. Methods: A cross-sectional study using a sample of 664 school children from the MOVI-Kids study. Variables: i) cognitive function measured by the Battery of General and Differential Aptitudes (BADyG); ii) birth weight, reported by parents; and iii) CRF (20-m shuttle run test). ANCOVA models were estimated to assess differences in cognitive function categories across birth weight and CRF categories. Mediation analysis was conducted with Hayes' PROCESS macro. Results: CRF is a full mediator of the association between birth weight with the verbal and numerical factors, and general intelligence; and is a partial mediator when logical reasoning and the spatial factor were the dependent variables. The available data suggest that, in schoolchildren, the influence of birth weight on cognitive function is mediated by CRF. Conclusions: These findings highlight that children with lower birth weight values and lower fitness levels should be target subgroups to improve children's cognition, in which long-life physical activity interventions at early ages are a priority.

The subject-dependent, cumulative, and recency association of aerobic fitness with academic performance in Taiwanese junior high school students

BACKGROUND

The objective of the current study was to examine whether the relation between aerobic fitness and academic achievement during adolescence is subject-dependent, and to investigate cumulative and recency effects.

METHODS

This study made use of two nationwide datasets. The first was the aerobic fitness profile of junior high school students collected by the Ministry of Education in Taiwan. The second contained the scores on the Basic Competence Test for Junior High School Students (BCTJH). The sample consisted of 382,259 students who completed the BCTJH in the 5 years between 2009 and 2013. Data on each student's aerobic fitness during their three years of junior high school were matched with their exam results at the end of this period.

RESULTS

The results revealed that students classified as highly-fit during at least one of the three years had higher BCTJH scores than those who never achieved this level, with the size of effect increasing with the length of time that fitness was maintained. Additionally, aerobic fitness in the final year was more closely linked to BCTJH scores than that in the earlier two years. Fitness was also more strongly associated with exam performance in math, science and social science, relative to language-related subjects.

CONCLUSIONS

Our findings suggest that while aerobic fitness is positively related to academic achievement in Taiwanese junior high school students, the relationship depends on academic subject, as well as the length and time of being aerobically fit.

Physical Activity Increases White Matter Microstructure in Children

Children are becoming increasingly inactive, unfit, and overweight, yet there is relatively little causal evidence regarding the effects of physical activity on brain health during childhood. The present study examined the effects of an after-school physical activity program (FITKids2) on the microstructure of white matter tracts in 7- to 9-year-old children. We measured the microstructural properties of white matter via diffusion tensor imaging in 143 children before and after random assignment to either a 9-month after-school physical activity program (N = 76, mean age = 8.7 years) or a wait list control group (N = 67, mean age = 8.7 years). Our results demonstrate that children who participated in the physical activity program showed increased white matter microstructure in the genu of the corpus callosum, with no changes in white matter microstructure in the wait list control group which reflects typical development. Specifically, children in the physical activity program showed increases in fractional anisotropy (FA) and decreases in radial diffusivity (RD) in the genu from pre- to post-test, thereby suggesting more tightly bundled and structurally compact fibers (FA) and increased myelination (RD), with no changes in estimates of axonal fiber diameter (axial diffusivity, AD). The corpus callosum integrates cognitive, motor, and sensory information between the left and right hemispheres of the brain, and the white matter tract plays a role in cognition and behavior. Our findings reinforce the importance of physical activity for brain health during child development.

Physical Activity, Health-Related Fitness, and Classroom Behavior in Children: A Discriminant Function Analysis

PURPOSE

The purpose of this study was to examine the predictive relationship among physical activity, health-related fitness, and on-task classroom behavior in children using a discriminant function analysis.

METHOD

Participants were a convenience sample of children (N = 533; M_age = 8.8 ± 1.9 years) recruited from 77 1st- through 5th-grade classrooms at 3 low-income schools in a capital city in the Southwest United States. Percent of the school day spent in sedentary behavior (%SED), moderate-to-vigorous physical activity (%MVPA), and health-related fitness scores (body mass index [BMI] and Progressive Aerobic Cardiovascular Endurance Run [PACER] laps) were assessed during school hours. Classrooms were observed for on-task behavior during the academic year with the use of 5-s momentary time sampling methodology. A discriminant function analysis was performed using a binary on-task behavior outcome, stratified by an 80% on-task behavior cut point.

RESULTS

The results yielded 1 function (r² = .26, F = 13.1) explaining approximately one quarter of the total variance. The standardized function coefficients were -.29, .29, -.48, and .48 for %SED, %MVPA, BMI, and PACER laps, respectively. The sensitivity and specificity of the derived function for classifying a child into an on-task or off-task classroom were .79 and .73, respectively. Children who belonged to classrooms that achieved 80% on-task behavior displayed shorter times in sedentary behaviors (d = 1.01), lower BMI (d = 0.13), and higher PACER scores (d = 0.22) compared with children who belonged to off-task classrooms.

CONCLUSION

School-day physical activity behaviors and health-related fitness scores can moderately discriminate children who belong to classrooms from low-income schools that are categorized as being sufficiently on task.

Weight loss, behavioral change, and structural neuroplasticity in children with obesity through a multidisciplinary treatment program

This study evaluated the effect of a multidisciplinary treatment program for children with obesity (OB) on motor competence, executive functioning (EF), and brain structure. Nineteen children with OB (7-11 years), who attended a multidisciplinary treatment program consisting of diet restriction, cognitive behavioral therapy, and physical activity, were compared with an age-matched control group of 24 children with a healthy weight (HW), who did not follow any treatment. For both groups, anthropometric measurements and tests of motor competence and EF were administered twice, with 5 months between pretest and posttest. Additionally, children's brain structure was assessed by performing a magnetic resonance imaging (MRI) scan at the pretest and posttest, which included a T1 anatomical scan, diffusion MRI scan, and magnetization transfer imaging scan. Compared to HW controls, children with OB lost a considerable amount of their body mass (p ≤ .001) and significantly improved their balance skills (p ≤ .001), while no transfer effects of the program were observed for EF. Furthermore, the program resulted in a significant increase in total (p ≤ .001) and cerebellar (p ≤ .001) gray matter volume in children with OB, while no change was observed in the HW controls. Finally, only weak to moderate (nonsignificant) correlations could be observed between structural brain alterations, weight-related changes, and behavioral improvements. Altogether, this is the first longitudinal study showing behavioral and structural brain alterations in response to a multidisciplinary weight loss program for children with OB. Our findings support the need for multidimensional intervention (and prevention) measures for children with OB to deal with this multifactorial health problem.

Combined Effects of Physical Activity and Obesity on Cognitive Function: Independent, Overlapping, Moderator, and Mediator Models

This article reviews studies on physical activity, obesity, and cognition to explore how physical activity and obesity may work independently or together in affecting cognitive function. In particular, we propose six hypotheses derived from four conceptual models to advance our understanding of the combined effects of physical activity and obesity on cognition. The four conceptual models are distinguished by the presumed temporal relationship and the presumed correlation between physical activity and obesity and include an independent model, an overlapping model, a moderator model, and a mediator model. Among the 16 studies testing the effects of physical activity and obesity on cognition in a combined approach, the moderator model, viewing either physical activity or obesity as the potential moderator, was most frequently examined (n = 10), mediator (n = 3) and independent (n = 2) models received relatively less attention, and only a single study used an overlapping model. Results were mixed when considering the moderator, independent, and mediator models. The single study that took an overlapping model approach found support for the model hypothesis. One relevant observation from this review is that the variance within the small extant literature with respect to the choice of conceptual model limits our ability to make assertive conclusions relative to the relations among the examined variables. Given the logic supporting a combined effect of physical activity and obesity on cognition, researchers are encouraged to consider the possible models of the relationship as they design studies to further address this research question.

Aerobic Exercise Intervention Alters Executive Function and White Matter Integrity in Deaf Children: A Randomized Controlled Study

This study examined the effects of an 11-week aerobic exercise intervention on executive function (EF) and white matter integrity (WMI). In total, 28 deaf children (aged 9-13 years) were randomly assigned to either an 11-week exercise intervention or the control group. All the children had behavioral assessment and diffusion tensor imaging prior to and following the exercise intervention. The behavioral performance results demonstrated that EF was enhanced by exercise. Relative to the control group, WMI of the exercise intervention group showed (1) lower fractional anisotropy (FA) in the pontine crossing tract (PCT) and right cingulum (hippocampus) (CH), genu of the corpus callosum (gCC), right inferior cerebellar peduncle (ICP), left superior corona radiata (SCR), and left superior frontooccipital fasciculus (SFOF); (2) higher mean diffusivity (MD) in the gCC, right CH, right inferior frontooccipital fasciculus (IFOF), and left anterior limb of the internal capsule (ALIC); and (3) lower MD in the left ICP and left tapetum (TAP). Furthermore, the lower FA in gCC showed a significant negative correlation with improvement in behavioral performance, but the correlation was not significant after FDR correction. These results suggest that exercise can effectively improve deaf children's EF and reshape the WMI in deaf children. The improved EF by exercise is not related to a reshaping of WMI, but more studies on the relationship between EF and WMI by exercise may be needed.

Physical activity, diet and other behavioural interventions for improving cognition and school achievement in children and adolescents with obesity or overweight

BACKGROUND

The global prevalence of childhood and adolescent obesity is high. Lifestyle changes towards a healthy diet, increased physical activity and reduced sedentary activities are recommended to prevent and treat obesity. Evidence suggests that changing these health behaviours can benefit cognitive function and school achievement in children and adolescents in general. There are various theoretical mechanisms that suggest that children and adolescents with excessive body fat may benefit particularly from these interventions.

OBJECTIVES

To assess whether lifestyle interventions (in the areas of diet, physical activity, sedentary behaviour and behavioural therapy) improve school achievement, cognitive function (e.g. executive functions) and/or future success in children and adolescents with obesity or overweight, compared with standard care, waiting-list control, no treatment, or an attention placebo control group.

SEARCH METHODS

In February 2017, we searched CENTRAL, MEDLINE and 15 other databases. We also searched two trials registries, reference lists, and handsearched one journal from inception. We also contacted researchers in the field to obtain unpublished data.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) of behavioural interventions for weight management in children and adolescents with obesity or overweight. We excluded studies in children and adolescents with medical conditions known to affect weight status, school achievement and cognitive function. We also excluded self- and parent-reported outcomes.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected studies for inclusion. Two review authors extracted data, assessed quality and risks of bias, and evaluated the quality of the evidence using the GRADE approach. We contacted study authors to obtain additional information. We used standard methodological procedures expected by Cochrane. Where the same outcome was assessed across different intervention types, we reported standardised effect sizes for findings from single-study and multiple-study analyses to allow comparison of intervention effects across intervention types. To ease interpretation of the effect size, we also reported the mean difference of effect sizes for single-study outcomes.

MAIN RESULTS

We included 18 studies (59 records) of 2384 children and adolescents with obesity or overweight. Eight studies delivered physical activity interventions, seven studies combined physical activity programmes with healthy lifestyle education, and three studies delivered dietary interventions. We included five RCTs and 13 cluster-RCTs. The studies took place in 10 different countries. Two were carried out in children attending preschool, 11 were conducted in primary/elementary school-aged children, four studies were aimed at adolescents attending secondary/high school and one study included primary/elementary and secondary/high school-aged children. The number of studies included for each outcome was low, with up to only three studies per outcome. The quality of evidence ranged from high to very low and 17 studies had a high risk of bias for at least one item. None of the studies reported data on additional educational support needs and adverse events.Compared to standard practice, analyses of physical activity-only interventions suggested high-quality evidence for improved mean cognitive executive function scores. The mean difference (MD) was 5.00 scale points higher in an after-school exercise group compared to standard practice (95% confidence interval (CI) 0.68 to 9.32; scale mean 100, standard deviation 15; 116 children, 1 study). There was no statistically significant beneficial effect in favour of the intervention for mathematics, reading, or inhibition control. The standardised mean difference (SMD) for mathematics was 0.49 (95% CI -0.04 to 1.01; 2 studies, 255 children, moderate-quality evidence) and for reading was 0.10 (95% CI -0.30 to 0.49; 2 studies, 308 children, moderate-quality evidence). The MD for inhibition control was -1.55 scale points (95% CI -5.85 to 2.75; scale range 0 to 100; SMD -0.15, 95% CI -0.58 to 0.28; 1 study, 84 children, very low-quality evidence). No data were available for average achievement across subjects taught at school.There was no evidence of a beneficial effect of physical activity interventions combined with healthy lifestyle education on average achievement across subjects taught at school, mathematics achievement, reading achievement or inhibition control. The MD for average achievement across subjects taught at school was 6.37 points lower in the intervention group compared to standard practice (95% CI -36.83 to 24.09; scale mean 500, scale SD 70; SMD -0.18, 95% CI -0.93 to 0.58; 1 study, 31 children, low-quality evidence). The effect estimate for mathematics achievement was SMD 0.02 (95% CI -0.19 to 0.22; 3 studies, 384 children, very low-quality evidence), for reading achievement SMD 0.00 (95% CI -0.24 to 0.24; 2 studies, 284 children, low-quality evidence), and for inhibition control SMD -0.67 (95% CI -1.50 to 0.16; 2 studies, 110 children, very low-quality evidence). No data were available for the effect of combined physical activity and healthy lifestyle education on cognitive executive functions.There was a moderate difference in the average achievement across subjects taught at school favouring interventions targeting the improvement of the school food environment compared to standard practice in adolescents with obesity (SMD 0.46, 95% CI 0.25 to 0.66; 2 studies, 382 adolescents, low-quality evidence), but not with overweight. Replacing packed school lunch with a nutrient-rich diet in addition to nutrition education did not improve mathematics (MD -2.18, 95% CI -5.83 to 1.47; scale range 0 to 69; SMD -0.26, 95% CI -0.72 to 0.20; 1 study, 76 children, low-quality evidence) and reading achievement (MD 1.17, 95% CI -4.40 to 6.73; scale range 0 to 108; SMD 0.13, 95% CI -0.35 to 0.61; 1 study, 67 children, low-quality evidence).

AUTHORS' CONCLUSIONS

Despite the large number of childhood and adolescent obesity treatment trials, we were only able to partially assess the impact of obesity treatment interventions on school achievement and cognitive abilities. School and community-based physical activity interventions as part of an obesity prevention or treatment programme can benefit executive functions of children with obesity or overweight specifically. Similarly, school-based dietary interventions may benefit general school achievement in children with obesity. These findings might assist health and education practitioners to make decisions related to promoting physical activity and healthy eating in schools. Future obesity treatment and prevention studies in clinical, school and community settings should consider assessing academic and cognitive as well as physical outcomes.

Physical activity, diet and other behavioural interventions for improving cognition and school achievement in children and adolescents with obesity or overweight

BACKGROUND

The global prevalence of childhood and adolescent obesity is high. Lifestyle changes towards a healthy diet, increased physical activity and reduced sedentary activities are recommended to prevent and treat obesity. Evidence suggests that changing these health behaviours can benefit cognitive function and school achievement in children and adolescents in general. There are various theoretical mechanisms that suggest that children and adolescents with excessive body fat may benefit particularly from these interventions.

OBJECTIVES

To assess whether lifestyle interventions (in the areas of diet, physical activity, sedentary behaviour and behavioural therapy) improve school achievement, cognitive function (e.g. executive functions) and/or future success in children and adolescents with obesity or overweight, compared with standard care, waiting-list control, no treatment, or an attention placebo control group.

SEARCH METHODS

In February 2017, we searched CENTRAL, MEDLINE and 15 other databases. We also searched two trials registries, reference lists, and handsearched one journal from inception. We also contacted researchers in the field to obtain unpublished data.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) of behavioural interventions for weight management in children and adolescents with obesity or overweight. We excluded studies in children and adolescents with medical conditions known to affect weight status, school achievement and cognitive function. We also excluded self- and parent-reported outcomes.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected studies for inclusion. Two review authors extracted data, assessed quality and risks of bias, and evaluated the quality of the evidence using the GRADE approach. We contacted study authors to obtain additional information. We used standard methodological procedures expected by Cochrane. Where the same outcome was assessed across different intervention types, we reported standardised effect sizes for findings from single-study and multiple-study analyses to allow comparison of intervention effects across intervention types. To ease interpretation of the effect size, we also reported the mean difference of effect sizes for single-study outcomes.

MAIN RESULTS

We included 18 studies (59 records) of 2384 children and adolescents with obesity or overweight. Eight studies delivered physical activity interventions, seven studies combined physical activity programmes with healthy lifestyle education, and three studies delivered dietary interventions. We included five RCTs and 13 cluster-RCTs. The studies took place in 10 different countries. Two were carried out in children attending preschool, 11 were conducted in primary/elementary school-aged children, four studies were aimed at adolescents attending secondary/high school and one study included primary/elementary and secondary/high school-aged children. The number of studies included for each outcome was low, with up to only three studies per outcome. The quality of evidence ranged from high to very low and 17 studies had a high risk of bias for at least one item. None of the studies reported data on additional educational support needs and adverse events.Compared to standard practice, analyses of physical activity-only interventions suggested high-quality evidence for improved mean cognitive executive function scores. The mean difference (MD) was 5.00 scale points higher in an after-school exercise group compared to standard practice (95% confidence interval (CI) 0.68 to 9.32; scale mean 100, standard deviation 15; 116 children, 1 study). There was no statistically significant beneficial effect in favour of the intervention for mathematics, reading, or inhibition control. The standardised mean difference (SMD) for mathematics was 0.49 (95% CI -0.04 to 1.01; 2 studies, 255 children, moderate-quality evidence) and for reading was 0.10 (95% CI -0.30 to 0.49; 2 studies, 308 children, moderate-quality evidence). The MD for inhibition control was -1.55 scale points (95% CI -5.85 to 2.75; scale range 0 to 100; SMD -0.15, 95% CI -0.58 to 0.28; 1 study, 84 children, very low-quality evidence). No data were available for average achievement across subjects taught at school.There was no evidence of a beneficial effect of physical activity interventions combined with healthy lifestyle education on average achievement across subjects taught at school, mathematics achievement, reading achievement or inhibition control. The MD for average achievement across subjects taught at school was 6.37 points lower in the intervention group compared to standard practice (95% CI -36.83 to 24.09; scale mean 500, scale SD 70; SMD -0.18, 95% CI -0.93 to 0.58; 1 study, 31 children, low-quality evidence). The effect estimate for mathematics achievement was SMD 0.02 (95% CI -0.19 to 0.22; 3 studies, 384 children, very low-quality evidence), for reading achievement SMD 0.00 (95% CI -0.24 to 0.24; 2 studies, 284 children, low-quality evidence), and for inhibition control SMD -0.67 (95% CI -1.50 to 0.16; 2 studies, 110 children, very low-quality evidence). No data were available for the effect of combined physical activity and healthy lifestyle education on cognitive executive functions.There was a moderate difference in the average achievement across subjects taught at school favouring interventions targeting the improvement of the school food environment compared to standard practice in adolescents with obesity (SMD 0.46, 95% CI 0.25 to 0.66; 2 studies, 382 adolescents, low-quality evidence), but not with overweight. Replacing packed school lunch with a nutrient-rich diet in addition to nutrition education did not improve mathematics (MD -2.18, 95% CI -5.83 to 1.47; scale range 0 to 69; SMD -0.26, 95% CI -0.72 to 0.20; 1 study, 76 children, low-quality evidence) and reading achievement (MD 1.17, 95% CI -4.40 to 6.73; scale range 0 to 108; SMD 0.13, 95% CI -0.35 to 0.61; 1 study, 67 children, low-quality evidence).

AUTHORS' CONCLUSIONS

Despite the large number of childhood and adolescent obesity treatment trials, we were only able to partially assess the impact of obesity treatment interventions on school achievement and cognitive abilities. School and community-based physical activity interventions as part of an obesity prevention or treatment programme can benefit executive functions of children with obesity or overweight specifically. Similarly, school-based dietary interventions may benefit general school achievement in children with obesity. These findings might assist health and education practitioners to make decisions related to promoting physical activity and healthy eating in schools. Future obesity treatment and prevention studies in clinical, school and community settings should consider assessing academic and cognitive as well as physical outcomes.

Diffusion MRI of white matter microstructure development in childhood and adolescence: Methods, challenges and progress

Diffusion magnetic resonance imaging (dMRI) continues to grow in popularity as a useful neuroimaging method to study brain development, and longitudinal studies that track the same individuals over time are emerging. Over the last decade, seminal work using dMRI has provided new insights into the development of brain white matter (WM) microstructure, connections and networks throughout childhood and adolescence. This review provides an introduction to dMRI, both diffusion tensor imaging (DTI) and other dMRI models, as well as common acquisition and analysis approaches. We highlight the difficulties associated with ascribing these imaging measurements and their changes over time to specific underlying cellular and molecular events. We also discuss selected methodological challenges that are of particular relevance for studies of development, including critical choices related to image acquisition, image analysis, quality control assessment, and the within-subject and longitudinal reliability of dMRI measurements. Next, we review the exciting progress in the characterization and understanding of brain development that has resulted from dMRI studies in childhood and adolescence, including brief overviews and discussions of studies focusing on sex and individual differences. Finally, we outline future directions that will be beneficial to the field.

Physical Activity, Fitness, Cognitive Function, and Academic Achievement in Children: A Systematic Review

BACKGROUND

The relationship among physical activity (PA), fitness, cognitive function, and academic achievement in children is receiving considerable attention. The utility of PA to improve cognition and academic achievement is promising but uncertain; thus, this position stand will provide clarity from the available science.

OBJECTIVE

The purpose of this study was to answer the following questions: 1) among children age 5-13 yr, do PA and physical fitness influence cognition, learning, brain structure, and brain function? 2) Among children age 5-13 yr, do PA, physical education (PE), and sports programs influence standardized achievement test performance and concentration/attention?

STUDY ELIGIBILITY CRITERIA

This study used primary source articles published in English in peer-reviewed journals. Articles that presented data on, PA, fitness, or PE/sport participation and cognition, learning, brain function/structure, academic achievement, or concentration/attention were included.

DATA SOURCES

Two separate searches were performed to identify studies that focused on 1) cognition, learning, brain structure, and brain function and 2) standardized achievement test performance and concentration/attention. PubMed, ERIC, PsychInfo, SportDiscus, Scopus, Web of Science, Academic Search Premier, and Embase were searched (January 1990-September 2014) for studies that met inclusion criteria. Sixty-four studies met inclusion criteria for the first search (cognition/learning/brain), and 73 studies met inclusion criteria for the second search (academic achievement/concentration).

STUDY APPRAISAL AND SYNTHESIS METHODS

Articles were grouped by study design as cross-sectional, longitudinal, acute, or intervention trials. Considerable heterogeneity existed for several important study parameters; therefore, results were synthesized and presented by study design.

RESULTS

A majority of the research supports the view that physical fitness, single bouts of PA, and PA interventions benefit children's cognitive functioning. Limited evidence was available concerning the effects of PA on learning, with only one cross-sectional study meeting the inclusion criteria. Evidence indicates that PA has a relationship to areas of the brain that support complex cognitive processes during laboratory tasks. Although favorable results have been obtained from cross-sectional and longitudinal studies related to academic achievement, the results obtained from controlled experiments evaluating the benefits of PA on academic performance are mixed, and additional, well-designed studies are needed.

LIMITATIONS

Limitations in evidence meeting inclusion criteria for this review include lack of randomized controlled trials, limited studies that are adequately powered, lack of information on participant characteristics, failure to blind for outcome measures, proximity of PA to measurement outcomes, and lack of accountability for known confounders. Therefore, many studies were ranked as high risk for bias because of multiple design limitations.

CONCLUSIONS

The present systematic review found evidence to suggest that there are positive associations among PA, fitness, cognition, and academic achievement. However, the findings are inconsistent, and the effects of numerous elements of PA on cognition remain to be explored, such as type, amount, frequency, and timing. Many questions remain regarding how to best incorporate PA within schools, such as activity breaks versus active lessons in relation to improved academic achievement. Regardless, the literature suggests no indication that increases in PA negatively affect cognition or academic achievement and PA is important for growth and development and general health. On the basis of the evidence available, the authors concluded that PA has a positive influence on cognition as well as brain structure and function; however, more research is necessary to determine mechanisms and long-term effect as well as strategies to translate laboratory findings to the school environment. Therefore, the evidence category rating is B. The literature suggests that PA and PE have a neutral effect on academic achievement. Thus, because of the limitations in the literature and the current information available, the evidence category rating for academic achievement is C.

Are Early Physical Activity and Sedentary Behaviors Related to Working Memory at 7 and 14 Years of Age?

OBJECTIVE

To evaluate the role of extracurricular physical activity and sedentary behavior at preschool and primary school age on working memory at primary school age and adolescence, respectively.

STUDY DESIGN

This prospective study was based on a birth cohort across 4 Spanish regions. In the 3 younger subcohorts (n = 1093), parents reported lifestyle habits of child at age 4 years of age on a questionnaire, and children performed a computerized working memory task at 7 years of age. In the older subcohort (n = 307), the questionnaire was completed at 6 years of age and working memory was tested at 14 years of age. Adjusted regression models were developed to investigate the associations between lifestyle habits and working memory.

RESULTS

Low extracurricular physical activity levels at 4 years of age were associated with a nonsignificant 0.95% (95% CI -2.81 to 0.92) reduction of correct responses in the working memory task at age 7 years of age. Low extracurricular physical activity levels at 6 years of age were associated with a 4.22% (95% CI -8.05 to -0.39) reduction of correct responses at age 14 years. Television watching was not associated with working memory. Other sedentary behaviors at 6 year of age were associated with a 5.07% (95% CI -9.68 to -0.46) reduction of correct responses in boys at 14 years of age.

CONCLUSION

Low extracurricular physical activity levels at preschool and primary school ages were associated with poorer working memory performance at primary school age and adolescence, respectively. High sedentary behavior levels at primary school age were related negatively to working memory in adolescent boys.

Diet, physical activity and behavioural interventions for the treatment of overweight or obese children from the age of 6 to 11 years

BACKGROUND

Child and adolescent overweight and obesity has increased globally, and can be associated with significant short- and long-term health consequences. This is an update of a Cochrane review published first in 2003, and updated previously in 2009. However, the update has now been split into six reviews addressing different childhood obesity treatments at different ages.

OBJECTIVES

To assess the effects of diet, physical activity and behavioural interventions (behaviour-changing interventions) for the treatment of overweight or obese children aged 6 to 11 years.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS as well as trial registers ClinicalTrials.gov and ICTRP Search Portal. We checked references of studies and systematic reviews. We did not apply any language restrictions. The date of the last search was July 2016 for all databases.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of diet, physical activity, and behavioural interventions (behaviour-changing interventions) for treating overweight or obese children aged 6 to 11 years, with a minimum of six months' follow-up. We excluded interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references, extracted data, assessed risk of bias, and evaluated the quality of the evidence using the GRADE instrument. We contacted study authors for additional information. We carried out meta-analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 70 RCTs with a total of 8461 participants randomised to either the intervention or control groups. The number of participants per trial ranged from 16 to 686. Fifty-five trials compared a behaviour-changing intervention with no treatment/usual care control and 15 evaluated the effectiveness of adding an additional component to a behaviour-changing intervention. Sixty-four trials were parallel RCTs, and four were cluster RCTs. Sixty-four trials were multicomponent, two were diet only and four were physical activity only interventions. Ten trials had more than two arms. The overall quality of the evidence was low or very low and 62 trials had a high risk of bias for at least one criterion. Total duration of trials ranged from six months to three years. The median age of participants was 10 years old and the median BMI z score was 2.2.Primary analyses demonstrated that behaviour-changing interventions compared to no treatment/usual care control at longest follow-up reduced BMI, BMI z score and weight. Mean difference (MD) in BMI was -0.53 kg/m2 (95% confidence interval (CI) -0.82 to -0.24); P < 0.00001; 24 trials; 2785 participants; low-quality evidence. MD in BMI z score was -0.06 units (95% CI -0.10 to -0.02); P = 0.001; 37 trials; 4019 participants; low-quality evidence and MD in weight was -1.45 kg (95% CI -1.88 to -1.02); P < 0.00001; 17 trials; 1774 participants; low-quality evidence.Thirty-one trials reported on serious adverse events, with 29 trials reporting zero occurrences RR 0.57 (95% CI 0.17 to 1.93); P = 0.37; 4/2105 participants in the behaviour-changing intervention groups compared with 7/1991 participants in the comparator groups). Few trials reported health-related quality of life or behaviour change outcomes, and none of the analyses demonstrated a substantial difference in these outcomes between intervention and control. In two trials reporting on minutes per day of TV viewing, a small reduction of 6.6 minutes per day (95% CI -12.88 to -0.31), P = 0.04; 2 trials; 55 participants) was found in favour of the intervention. No trials reported on all-cause mortality, morbidity or socioeconomic effects, and few trials reported on participant views; none of which could be meta-analysed.As the meta-analyses revealed substantial heterogeneity, we conducted subgroup analyses to examine the impact of type of comparator, type of intervention, risk of attrition bias, setting, duration of post-intervention follow-up period, parental involvement and baseline BMI z score. No subgroup effects were shown for any of the subgroups on any of the outcomes. Some data indicated that a reduction in BMI immediately post-intervention was no longer evident at follow-up at less than six months, which has to be investigated in further trials.

AUTHORS' CONCLUSIONS

Multi-component behaviour-changing interventions that incorporate diet, physical activity and behaviour change may be beneficial in achieving small, short-term reductions in BMI, BMI z score and weight in children aged 6 to 11 years. The evidence suggests a very low occurrence of adverse events. The quality of the evidence was low or very low. The heterogeneity observed across all outcomes was not explained by subgrouping. Further research is required of behaviour-changing interventions in lower income countries and in children from different ethnic groups; also on the impact of behaviour-changing interventions on health-related quality of life and comorbidities. The sustainability of reduction in BMI/BMI z score and weight is a key consideration and there is a need for longer-term follow-up and further research on the most appropriate forms of post-intervention maintenance in order to ensure intervention benefits are sustained over the longer term.

A Conceptual Neurocognitive Affect-Related Model for the Promotion of Exercise Among Obese Adults

PURPOSE OF REVIEW

Obesity remains a prominent societal threat and burden despite well-promoted prevention and treatment strategies, such as regular engagement in physical activity. Obese individuals, in particular, may be prone to inactivity as a result of a variety of displeasure-related parameters resulting from exercise, such as dyspnea, for instance.

RECENT FINDINGS

This brief conceptual review discusses the integral roles of exercise-induced affective responses within a novel conceptual-based neurocognitive affect-related model. Specifically, this model includes three pathways: (1) pathway A proposes that neurocognition, and especially, executive function-based cognition, may play an influential role in fostering exercise-induced affective responses, (2) pathway B connects an individual's affective response from exercise to their future exercise behavior, and (3) pathway C suggests a cyclical, bi-directional relationship with executive function indirectly influencing future exercise behavior via affective responses to exercise, and exercise itself playing an important role in executive functioning. Future studies should empirically test this model, which may have utility for promoting exercise among the obese population.

Cardiorespiratory fitness and white matter integrity in Alzheimer's disease

The objective of this study was to investigate the relationship between cardiorespiratory (CR) fitness and the brain's white matter tract integrity using diffusion tensor imaging (DTI) in the Alzheimer's disease (AD) population. We recruited older adults in the early stages of AD (n = 37; CDR = 0.5 and 1) and collected cross-sectional fitness and diffusion imaging data. We examined the association between CR fitness (peak oxygen consumption [VO2peak]) and fractional anisotropy (FA) in AD-related white matter tracts using two processing methodologies: a tract-of-interest approach and tract-based spatial statistic (TBSS). Subsequent diffusivity metrics (radial diffusivity [RD], mean diffusivity [MD], and axial diffusivity [A × D]) were also correlated with VO2peak. The tract-of-interest approach showed that higher VO2peak was associated with preserved white matter integrity as measured by increased FA in the right inferior fronto-occipital fasciculus (p = 0.035, r = 0.36). We did not find a significant correlation using TBSS, though there was a trend for a positive association between white matter integrity and higher VO2peak measures (p < 0.01 uncorrected). Our findings indicate that higher CR fitness levels in early AD participants may be related to preserved white matter integrity. However to draw stronger conclusions, further study on the relationship between fitness and white matter deterioration in AD is necessary.

Physical Activity for Cognitive and Mental Health in Youth: A Systematic Review of Mechanisms

CONTEXT

Physical activity can improve cognitive and mental health, but the underlying mechanisms have not been established.

OBJECTIVE

To present a conceptual model explaining the mechanisms for the effect of physical activity on cognitive and mental health in young people and to conduct a systematic review of the evidence.

DATA SOURCES

Six electronic databases (PubMed, PsycINFO, SCOPUS, Ovid Medline, SportDiscus, and Embase) were used.

STUDY SELECTION

School-, home-, or community-based physical activity intervention or laboratory-based exercise interventions were assessed. Studies were eligible if they reported statistical analyses of changes in the following: (1) cognition or mental health; and (2) neurobiological, psychosocial, and behavioral mechanisms.

DATA EXTRACTION

Data relating to methods, assessment period, participant characteristics, intervention type, setting, and facilitator/delivery were extracted.

RESULTS

Twenty-five articles reporting results from 22 studies were included. Mechanisms studied were neurobiological (6 studies), psychosocial (18 studies), and behavioral (2 studies). Significant changes in at least 1 potential neurobiological mechanism were reported in 5 studies, and significant effects for at least 1 cognitive outcome were also found in 5 studies. One of 2 studies reported a significant effect for self-regulation, but neither study reported a significant impact on mental health.

LIMITATIONS

Small number of studies and high levels of study heterogeneity.

CONCLUSIONS

The strongest evidence was found for improvements in physical self-perceptions, which accompanied enhanced self-esteem in the majority of studies measuring these outcomes. Few studies examined neurobiological and behavioral mechanisms, and we were unable to draw conclusions regarding their role in enhancing cognitive and mental health.

Randomized Controlled Trial of Exercise for ADHD and Disruptive Behavior Disorders

PURPOSE

The objective of this study is to test the feasibility and impact of a 10-wk after-school exercise program for children with attention deficit hyperactivity disorder and/or disruptive behavior disorders living in an urban poor community.

METHODS

Children were randomized to an exercise program (n = 19) or a comparable but sedentary attention control program (n = 16). Cognitive and behavioral outcomes were collected pre-/posttest. Intent-to-treat mixed models tested group-time and group-time-attendance interactions. Effect sizes were calculated within and between groups.

RESULTS

Feasibility was evidenced by 86% retention, 60% attendance, and average 75% maximum HR. Group-time results were null on the primary outcome, parent-reported executive function. Among secondary outcomes, between-group effect sizes favored exercise on hyperactive symptoms (d = 0.47) and verbal working memory (d = 0.26), and controls on visuospatial working memory (d = -0.21) and oppositional defiant symptoms (d = -0.37). In each group, within-group effect sizes were moderate to large on most outcomes (d = 0.67 to 1.60). A group-time-attendance interaction emerged on visuospatial working memory (F[1,33] = 7.42, P < 0.05), such that attendance to the control program was related to greater improvements (r = 0.72, P < 0.01), whereas attendance to the exercise program was not (r = 0.25, P = 0.34).

CONCLUSIONS

Although between-group findings on the primary outcome, parent-reported executive function, were null, between-group effect sizes on hyperactivity and visuospatial working memory may reflect adaptations to the specific challenges presented by distinct formats. Both groups demonstrated substantial within-group improvements on clinically relevant outcomes. Findings underscore the importance of programmatic features, such as routines, engaging activities, behavior management strategies, and adult attention, and highlight the potential for after-school programs to benefit children with attention deficit hyperactivity disorder and disruptive behavior disorder living in urban poverty where health needs are high and services resources few.

Physical Activity Interventions for Neurocognitive and Academic Performance in Overweight and Obese Youth: A Systematic Review

This article examines cognitive, academic, and brain outcomes of physical activity in overweight or obese youth, with attention to minority youth who experience health disparities. Physically active academic lessons may have greater immediate cognitive and academic benefits among overweight and obese children than normal-weight children. Quasi-experimental studies testing physical activity programs in overweight and obese youth show promise; a few randomized controlled trials including African Americans show efficacy. Thus, making academic lessons physically active may improve inhibition and attentiveness, particularly in overweight youngsters. Regular physical activity may be efficacious for improving neurologic, cognitive, and achievement outcomes in overweight or obese youth.

Lower Working Memory Performance in Overweight and Obese Adolescents Is Mediated by White Matter Microstructure

OBJECTIVES

Elevated body mass index (BMI) is associated with deficits in working memory, reduced gray matter volume in frontal and parietal lobes, as well as changes in white matter (WM) microstructure. The current study examined whether BMI was related to working memory performance and blood oxygen level dependent (BOLD) activity, as well as WM microstructure during adolescence.

METHODS

Linear regressions with BMI and (1) verbal working memory BOLD signal, (2) spatial working memory BOLD signal, and (3) fractional anisotropy (FA), a measure of WM microstructure, were conducted in a sample of 152 healthy adolescents ranging in BMI.

RESULTS

BMI was inversely related to IQ and verbal and spatial working memory accuracy; however, there was no significant relationship between BMI and BOLD response for either verbal or spatial working memory. Furthermore, BMI was negatively correlated with FA in the left superior longitudinal fasciculus (SLF) and left inferior longitudinal fasciculus (ILF). ILF FA and IQ significantly mediated the relationship between BMI and verbal working memory performance, whereas SLF FA, but not IQ, significantly mediated the relationship between BMI and accuracy of both verbal and spatial working memory.

CONCLUSIONS

These findings indicate that higher BMI is associated with decreased FA in WM fibers connecting brain regions that support working memory, and that WM microstructural deficits may underlie inferior working memory performance in youth with higher BMI. Of interest, BMI did not show the same relationship with working memory BOLD activity, which may indicate that changes in brain structure precede changes in function.

Independent Associations of Organized Physical Activity and Weight Status with Children's Cognitive Functioning: A Matched-Pairs Design

PURPOSE

This study tested whether participation in organized physical activity (active vs. inactive) or weight status (normal weight vs. overweight or obese) independently relate to children's cognition, using a matched-pairs design.

DESIGN AND METHODS

Normal weight, active children (8-11 yrs, 5th-75th percentile BMI) were recruited from extracurricular physical activity programs while normal weight inactive (5th-75th percentile BMI) and overweight inactive children (BMI ≥85th percentile) were recruited from local Augusta, Georgia area schools. Measures included the Cognitive Assessment System, anthropometrics, and parent- and self-report of physical activity. Paired t tests compared cognition scores between matched groups of normal weight active vs. normal weight inactive (N = 24 pairs), normal weight inactive vs. overweight inactive (N = 21 pairs), and normal weight active vs. overweight inactive children (N = 16 pairs). Children in each comparison were matched for race, gender, age, and socioeconomic status.

RESULTS

Normal weight active children had higher Planning (M± SD = 109 ± 11 vs. 100 ± 11, p = .011) and Attention scores (108 ± 11 vs. 100 ± 11, p = .013) than overweight inactive children. Normal weight inactive children had higher Attention scores than overweight inactive children (105 ± 13 vs. 93 ± 12, p = .008). When compared with normal weight inactive children, normal weight active children had higher Planning (113 ± 10 vs. 102 ± 13, p = .008) and marginally higher Attention scores (111 ± 11 vs. 104 ± 12, p = .06).

CONCLUSION

Findings suggest independent associations of children's weight status with selective attention, and physical activity with higher-order processes of executive function.

The Relationship of Health Behaviors to Childhood Cognition and Brain Health

Background: Physical activity and aerobic fitness have been shown to have positive implications for children's cognitive performance and brain structure and function. In addition, emerging evidence suggests that excess body mass is related to decreased cognitive performance and differential brain structure and function. Recently, several randomized controlled trials have provided causal evidence for the beneficial effects of daily physical activity on cognition and its neural underpinnings. However, the data linking excess body mass to compromised cognitive function are largely correlational since trials that manipulate body mass to determine changes in brain and cognition remain sparse. Such studies are sorely needed to provide strong evidence for the relation of childhood health behaviors to not only physical, but brain health as well. Summary: This manuscript provides a brief review of the current literature on physical activity and excess body mass on brain structure, brain function, and an aspect of cognition known as executive control, which refers to cognitive processes involved in the intentional component of environmental interaction. Generally, the findings indicate that daily physical activity or higher aerobic fitness is related to greater volume and integrity of brain structure, efficient and effective brain function, and superior executive control. Alternatively, excess body mass is related to decreased integrity of brain structure, less effective brain function, and poorer executive control. Key Messages: The findings have considerable implications for lifespan health and effective functioning, and demonstrate that childhood health behaviors have implications not only for cognitive and brain health but also for scholastic performance and educational attainment.

Society of Behavioral Medicine position statement: elementary school-based physical activity supports academic achievement

The Society of Behavioral Medicine (SBM) urges elementary schools to provide children with ample opportunities to engage in physical activity during school hours. In addition to promoting overall child health, physical activity also supports academic achievement. In addition to improving their aerobic fitness, regular physical activity improves cognitive function, influences the brain, and improves mood in children. Better aerobic fitness and physical activity are associated with increased grade point averages and standardized test scores. Despite the documented relationship between physical activity, fitness, and academic achievement, few schools have implemented physical activity as a tool to improve academic performance. SBM recommends that elementary schools provide children with the recommended 60 min of moderate-to-vigorous physical activity during school hours. Further, SBM urges schools to work with the local school districts and state education departments to mandate minimum physical activity time for elementary school physical education.

Effects of the FITKids randomized controlled trial on executive control and brain function

OBJECTIVE

To assess the effect of a physical activity (PA) intervention on brain and behavioral indices of executive control in preadolescent children.

METHODS

Two hundred twenty-one children (7-9 years) were randomly assigned to a 9-month afterschool PA program or a wait-list control. In addition to changes in fitness (maximal oxygen consumption), electrical activity in the brain (P3-ERP) and behavioral measures (accuracy, reaction time) of executive control were collected by using tasks that modulated attentional inhibition and cognitive flexibility.

RESULTS

Fitness improved more among intervention participants from pretest to posttest compared with the wait-list control (1.3 mL/kg per minute, 95% confidence interval [CI]: 0.3 to 2.4; d = 0.34 for group difference in pre-to-post change score). Intervention participants exhibited greater improvements from pretest to posttest in inhibition (3.2%, 95% CI: 0.0 to 6.5; d = 0.27) and cognitive flexibility (4.8%, 95% CI: 1.1 to 8.4; d = 0.35 for group difference in pre-to-post change score) compared with control. Only the intervention group increased attentional resources from pretest to posttest during tasks requiring increased inhibition (1.4 µV, 95% CI: 0.3 to 2.6; d = 0.34) and cognitive flexibility (1.5 µV, 95% CI: 0.6 to 2.5; d = 0.43). Finally, improvements in brain function on the inhibition task (r = 0.22) and performance on the flexibility task correlated with intervention attendance (r = 0.24).

CONCLUSIONS

The intervention enhanced cognitive performance and brain function during tasks requiring greater executive control. These findings demonstrate a causal effect of a PA program on executive control, and provide support for PA for improving childhood cognition and brain health.

An 8-month exercise intervention alters frontotemporal white matter integrity in overweight children

In childhood, excess adiposity and low fitness are linked to poor academic performance, lower cognitive function, and differences in brain structure. Identifying ways to mitigate obesity-related alterations is of current clinical importance. This study examined the effects of an 8-month exercise intervention on the uncinate fasciculus, a white matter fiber tract connecting frontal and temporal lobes. Participants consisted of 18 unfit, overweight 8- to 11-year-old children (94% Black) who were randomly assigned to either an aerobic exercise (n = 10) or a sedentary control group (n = 8). Before and after the intervention, all subjects participated in a diffusion tensor MRI scan. Tractography was conducted to isolate the uncinate fasciculus. The exercise group showed improved white matter integrity as compared to the control group. These findings are consistent with an emerging literature suggesting beneficial effects of exercise on white matter integrity.