Thursday, 20 January, 2022
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Children's brain structure affected by exercise

Researchers from the University of Granada (UGR) have proven, for the first time in history, that physical fitness in children may affect their brain structure, which in turn may have an influence on their academic performance. More specifically, the researchers have confirmed that physical fitness in children (especially aerobic capacity and motor ability) is associated with a greater volume of grey matter in several cortical and sub-cortical brain regions.

In particular, aerobic capacity has been associated with greater grey matter volume in frontal regions (premotor cortex and supplementary motor cortex), sub-cortical regions (hippocampus and caudate nucleus), temporal regions (inferior temporal gyrus and para-hippocampal gyrus) and the calcarine cortex. All of those regions are important for the executive function as well as for learning, motor and visual processes.

This study is part of the ActiveBrains project, which is a randomised clinical trial involving more than 100 overweight/obese children led by Dr Francisco B Ortega. Said project is being carried out mainly at the University of Granada's Sport and Health Institute (IMUDS, from its abbreviation in Spanish) and the Mind, Brain and Behaviour Research Centre (CIMCYC).

"Our work aims at answering questions such as whether the brain of children with better physical fitness is different from that of children with worse physical fitness and if this affects their academic performance," Ortega explains.

"The answer is short and forceful: yes, physical fitness in children is linked in a direct way to important brain structure differences, and such differences are reflected in the children's academic performance."

Besides, the UGR research associates motor ability with a greater grey matter volume in two regions essential for language processing and reading: the inferior frontal gyrus and the superior temporal gyrus. However, muscular strength didn't showed any independent association with grey matter volume in any brain region.

According to Dr Irene Esteban-Cornejo, postdoctoral researcher at the University of Granada and main author of this paper, grey matter volume in the cortical and subcortical regions influenced by physical fitness improves in turn the children's academic performance. Moreover, "physical fitness is a factor that can be modified through physical exercise, and combining exercises that improve the aerobic capacity and the motor ability would be an effective approach to stimulate brain development and academic performance in overweight/obese children."

This scientific paper means an important contribution to human knowledge which should be taken into account by educational and public health institutions.

"We appeal both to politicians, who make educational laws that are increasingly more focused on instrumental subjects, and to teachers, who are the final link in the chain and teach physical education day after day. School is the only entity that gathers every children in a mandatory way for a period of at least 10 years, and as such, it's the ideal context for applying such recommendations," note the researchers.

In their own words, the authors of this study are "at the disposal of educational and public health institutions for talking about possible measures and putting them into action."

Obesity, as compared to normal weight, is associated with detectable structural differences in the brain. To the best of our knowledge, no previous study has examined the association of physical fitness with gray matter volume in overweight/obese children using whole brain analyses. Thus, the aim of this study was to examine the association between the key components of physical fitness (i.e. cardiorespiratory fitness, speed-agility and muscular fitness) and brain structural volume, and to assess whether fitness-related changes in brain volumes are related to academic performance in overweight/obese children. A total of 101 overweight/obese children aged 8–11 years were recruited from Granada, Spain. The physical fitness components were assessed following the ALPHA health-related fitness test battery. T1-weighted images were acquired with a 3.0 T S Magnetom Tim Trio system. Gray matter tissue was calculated using Diffeomorphic Anatomical Registration Through Exponentiated Lie algebra (DARTEL). Academic performance was assessed by the Batería III Woodcock-Muñoz Tests of Achievement. All analyses were controlled for sex, peak high velocity offset, parent education, body mass index and total brain volume. The statistical threshold was calculated with AlphaSim and further Hayasaka adjusted to account for the non-isotropic smoothness of structural images. The main results showed that higher cardiorespiratory fitness was related to greater gray matter volumes (P < 0.001, k = 64) in 7 clusters with β ranging from 0.493 to 0.575; specifically in frontal regions (i.e. premotor cortex and supplementary motor cortex), subcortical regions (i.e. hippocampus and caudate), temporal regions (i.e. inferior temporal gyrus and parahippocampal gyrus) and calcarine cortex. Three of these regions (i.e. premotor cortex, supplementary motor cortex and hippocampus) were related to better academic performance (β ranging from 0.211 to 0.352; all P < 0.05). Higher speed-agility was associated with greater gray matter volumes (P < 0.001, k = 57) in 2 clusters (i.e. the inferior frontal gyrus and the superior temporal gyrus) with β ranging from 0.564 to 0.611. Both clusters were related to better academic performance (β ranging from 0.217 to 0.296; both P < 0.05). Muscular fitness was not independently associated with greater gray matter volume in any brain region. Furthermore, there were no statistically significant negative association between any component of physical fitness and gray matter volume in any region of the brain. In conclusion, cardiorespiratory fitness and speed-agility, but not muscular fitness, may independently be associated with greater volume of numerous cortical and subcortical brain structures; besides, some of these brain structures may be related to better academic performance. Importantly, the identified associations of fitness and gray matter volume were different for each fitness component. These findings suggest that increases in cardiorespiratory fitness and speed-agility may positively influence the development of distinctive brain regions and academic indicators, and thus counteract the harmful effect of overweight and obesity on brain structure during childhood.

Irene Esteban-Cornejo, Cristina Cadenas-Sanchez, Oren Contreras-Rodriguez, Juan Verdejo-Roman, Jose Mora-Gonzalez, Jairo H Migueles, Pontus Henriksson, Catherine L Davis, Antonio Verdejo-Garcia, Andrés Catena, Francisco B Ortega

[link url=""]University of Granada material[/link]
[link url=""]Neuroimage abstract[/link]

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