Pre-adolescence is a period of profound changes in the neural circuitry of the brain, vulnerable to risk factors such as being overweight. A recent study indicates that daily physical activity in this age group has both direct and indirect positive effects on brain development.

Regular, physical, activity, linked, to, more, "fit", brains, in, preteens
Beneficial for heart, body and mind health, exercise has many health benefits. A new study by researchers at Boston Children's Hospital adds another benefit for younger children: physical activity appears to help organize children's brain development, knowing that it is already recommended to promote healthy growth and development. The study, published in the journal Brain Cortex, analyzed brain imaging data from nearly 6,000 9- and 10-year-olds. Its results show that physical activity was associated with more efficiently organized and flexible brain networks.

Specifically, the more physical activity, the more "fit" the brain. "It didn't matter what type of physical activity the children were involved in," explains Dr. Caterina Stamoulis, "it just mattered that they were active." The researchers mined functional magnetic resonance brain imaging data from the Adolescent Brain Cognitive Development study, a long-term study sponsored by the National Institutes of Health. Their goal: to estimate the strength and organizational properties of the children's brain circuitry - how efficiently the brain functions and how easily it can adapt to changes in the environment.

One hour of physical activity several times a week

"Pre-adolescence is a very important period in brain development," notes Dr. Stamoulis. "It is associated with many changes in the brain's functional circuitry, particularly those that support high-level thinking processes. Unhealthy changes in these areas can lead to risky behaviors and lasting deficits in the skills needed for learning and reasoning." The scientific team combined the data obtained with information about the children's physical activity and sports participation, provided by the families, as well as their body mass index (BMI).

Finally, the scientists adjusted the data for other factors that could affect brain development, such as birth before 40 weeks gestation, puberty status, gender and family income. The results show that being physically active several times a week for at least 60 minutes has a generalized positive effect on brain circuits. For example, children who engaged in high levels of physical activity showed beneficial effects on brain circuits in several areas critical to learning and reasoning. These included attention, sensory and motor processing, memory, decision making and executive control.

A stronger connection between neurons

The latter ability involves planning, coordinating and controlling actions and behaviors. It turns out, however, that an increase in BMI had adverse effects on the same brain circuits, although regular physical activity reduced these negative effects. "We think that physical activity affects brain organization directly, but also indirectly by reducing BMI," notes Dr. Stamoulis. In the analyses, the brain was represented mathematically as a network of "nodes": a set of brain regions linked by connections of varying strength. Physical activity had two types of positive effects on these brain networks.

First, it had a positive impact on the efficiency and robustness of the network as a whole, and second, in more local ways such as the number and clustering of these "nodes. Yet, as Dr. Stamoulis points out, "highly connected local brain networks that communicate with each other through relatively few but robust long-range connections optimize information processing and transmission in the brain." "In preadolescents, a number of brain functions are still developing, and they may be impaired by a number of risk factors. Our results suggest that physical activity has a positive protective effect in all brain regions." she concludes.