Effects of Physical Activity and Micronutrients on Cognitive Performance in Children Aged 6 to 11 Years: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Grandfathers-to-Grandsons Transgenerational Transmission of Exercise Positive Effects on Cognitive Performance

Physical exercise is a robust lifestyle intervention known for its enhancement of cognitive abilities. Nevertheless, the extent to which these benefits can be transmitted across generations (intergenerational inheritance to F1, and transgenerational to F2 and beyond) remains a topic of limited comprehension. We have already shown that cognitive improvements resulting from physical exercise can be inherited from parents to their offspring, proving intergenerational effects. So, we set out to explore whether these enhancements might extend transgenerationally, impacting the F2 generation. In this study, we initially examined the behavioral traits of second generation (F2) male mice, whose grandfathers (F0) had an exercise intervention. Our findings revealed that F2 mice with physically active grandpaternal F0 progenitors displayed significantly improved memory recall, encompassing both spatial and non-spatial information when compared to their counterparts from sedentary F0 progenitors, and proving for the first time the transgenerational inheritance of physical exercise induced cognitive enhancement. Surprisingly, while F2 memory improved (as was the case with F1), adult hippocampal neurogenesis remained unchanged between experimental and control groups (unlike in F1). Additionally, our analysis of small RNA sequences in the hippocampus identified 35 differentially expressed miRNAs linked to important brain function categories. Notably, two of these miRNAs, miRNA-144 and miRNA-298, displayed a robust negative correlation with cognitive performance. These findings highlight the enduring transgenerational transmission of cognitive benefits associated with exercise, even after two generations, suggesting that moderate exercise training can have lasting positive effects, possibly orchestrated by a specific set of miRNAs that exert their influence across multiple generations.

Effect of Extracurricular After-School Physical Activities on Academic Performance of Schoolchildren: A Cluster Randomized Clinical Trial

Importance

The beneficial effects of increasing outdoor physical activity time on children's myopia onset and physical well-being are widely acknowledged. However, in countries with competitive educational systems, such as China, parents and school administrators may be relatively reluctant to increase the extracurricular physical activity time for children due to concerns that this action will compromise children's academic performance.

Objective

To investigate whether additional extracurricular physical activity time after school compromises the academic performance of schoolchildren.

Design, Setting, and Participants

This cluster randomized clinical trial was conducted from October 2020 to June 2021 in Yudu, Jiangxi, China. Eligible children in grades 3 and 4 from 24 elementary schools were randomized to the intervention or control group. Primary analysis was conducted in the full sample using the intention-to-treat principle.

Interventions

The intervention group received 2 hours of after-school physical activity time outdoors on school days. The control group was free to arrange their after-school activity.

Main Outcomes and Measures

The primary outcome was the between-group mean difference in mathematics test scores at the end of 1 academic year, with a noninferiority margin of -3.3 points. Standardized mathematics tests, physical fitness assessments (in reference to the 2018 National Physical Fitness Survey Monitoring Programme in China), and cycloplegic autorefraction were performed at baseline and the end of 1 academic year. Myopia was defined as a cycloplegic spherical equivalent refraction of -0.5 diopters or less in either eye.

Results

A total of 2032 children (mean [SD] age, 9.22 [0.62] years; 1040 girls [51.2%]) from 24 schools were randomized to the intervention group (12 schools; 1012 children) or control group (12 schools; 1020 children). The mean (SD) mathematics score at the end of 1 academic year was 78.01 (17.56) points in the intervention group and 77.70 (17.29) points in the control group. The adjusted between-group mean difference was 0.65 points (95% CI, -2.85 to 4.15). The adjusted between-group mean difference in physical fitness score was 4.95 points (95% CI, 3.56-6.34; P < .001) and -1.90% (95% CI, -18.72% to 14.91%; P > .99) in myopia incidence.

Conclusions and Relevance

Results of this trial indicate that, compared with the control practice of free play after school, adding 2 hours of extracurricular physical activity outdoors after school was noninferior in academic performance and had superior efficacy in improving physical fitness.

Trial Registration

ClinicalTrials.gov Identifier: NCT04587765.

An umbrella review of randomized control trials on the effects of physical exercise on cognition

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% confidence interval 0.16 to 0.28) that became substantially smaller after accounting for key moderators (that is, active control and baseline differences; d = 0.13, 95% confidence interval 0.07 to 0.20), and negligible after correcting for publication bias (d = 0.05, 95% confidence interval -0.09 to 0.14). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

Physical exercise ameliorates memory impairment in offspring of old mice

For humans, maternal old age means the age of 35 or older at the time of childbirth. Maternal metabolism not only affects the cognitive function of the offspring, but also affects their physical and neurological development. This study aims to elucidate the effects of exercise training on spatial learning memory, neurogenesis, and apoptosis in the off-spring of old mice. Using mice, the offspring of old mothers showed impaired spatial learning memory, decreased brain-derived neurotrophic factor and postsynaptic density protein 95 levels, suppressed neurogenesis, and increased hippocampal apoptotic cell death. In contrast, the offspring of the old mothers had improved spatial learning memory, increased brain-derived neurotrophic factor and postsynaptic density protein 95 levels, increased neurogenesis, and decreased hippocampal apoptotic cell death when they received exercise training. The present results indicate that there is apparent spatial learning memory impairment among the offspring of old mothers, but by contrast, exercise can ameliorate spatial learning memory impairment. Exercise can be an effective countermeasure against memory decline in the offspring of old mothers.

Evaluation of a Physical Activity and Multi-Micronutrient Intervention on Cognitive and Academic Performance in South African Primary Schoolchildren

Executive functions (EFs) are essential for optimal academic development. Appropriate nutrition and physical activity (PA) have been shown to facilitate optimal cognitive development. Therefore, this study examined whether a 12-week school-based PA and multi-micronutrient supplementation (MMNS) intervention would improve cognitive and academic performance. A cluster-randomized controlled trial (RCT) was conducted. Children from four schools located in a peri-urban area of South Africa were randomly assigned to (i) PA + MMNS, (ii) PA + placebo, (iii) MMNS or (iv) placebo. Information processing and inhibitory control were measured with a computerized Flanker task. End-of-year results provided insight into academic achievement. Anthropometric measures were used to determine nutritional status. Data were analyzed with linear mixed-models, adjusting for baseline scores, school classes and age; 932 children (458 girls (49.1%), M_age (mean age) = 8.42 ± 1.94 years) completed baseline and post-intervention assessments. Cognitive performance improved among all four groups, with no significant group × time effects. For academic achievement, there was no significant interaction effect between the combined intervention group and placebo. We encourage future studies in this neglected area in order to determine the most optimal design of school-based nutrition and PA programs to enhance overall cognitive performance.