redOrbit Staff & Wire Reports – Your Universe Online
Youngsters who are more physically fit have more fibrous and compact white-matter tracts in the brain than their less-fit counterparts, according to new research appearing in the August 19 edition of the journal Frontiers in Human Neuroscience.
Researchers from the University of Illinois at Urbana-Champaign, the University of Pittsburgh, the University of Iowa and Michigan State University recruited two dozen 9- and 10-year-old children, and then used a technique known as diffusion tensor imaging (DTI) to analyze water diffusion in tissues in five of their brains’ white-matter tracts.
After controlling for several variables, including each youngster’s IQ and whether or not they had been diagnosed with learning disabilities, the researchers determined significant fitness-related differences in the integrity of several white-matter tracts, including the corpus callosum (which connects the brain’s left and right hemispheres) and the superior longitudinal fasciculus (a pair of structures that connect the frontal and parietal lobes).
“Previous studies suggest that children with higher levels of aerobic fitness show greater brain volumes in gray-matter brain regions important for memory and learning,” study author Laura Chaddock-Heyman, a postdoctoral researcher at the University of Illinois’s department of psychology, said in a statement Tuesday. “Now for the first time we explored how aerobic fitness relates to white matter in children’s brains.”
While the study does not prove that physical fitness can actually make children smarter, it does provide evidence to support that notion, said HealthDay News reporter Randy Dotinga. While previous research had discovered an association between higher levels of fitness and improved attentiveness, memory and academic skills, Chaddock-Heyman and her colleagues set out to learn more about the impact of exercise in the brains of young children.
In addition to differences in the corpus callosum and the superior longitudinal fasciculus, the researchers also uncovered a link between fitness and the superior corona radiata, which connect the cerebral cortex to the brain stem. The researchers explained that all three of these tracts have been found to influence memory and attention.
“Previous studies in our lab have reported a relationship between fitness and white-matter integrity in older adults. Therefore, it appears that fitness may have beneficial effects on white matter throughout the lifespan,” said co-author psychology professor and Beckman Institute for Advanced Science and Technology director Arthur Kramer.
Chaddock-Heyman, Kramer and their colleagues are now looking to expand on their work, which is in the second year of a five-year randomized, controlled trial to determine whether or not white-matter tract integrity improves in youngsters who begin and maintain a new physical fitness routine. The researchers said that they are looking for changes in their subjects’ aerobic fitness levels, their brain structure and function, and their genetic regulation.
“Prior work from our laboratories has demonstrated both short- and long-term differences in the relation of aerobic fitness to brain health and cognition,” said University of Illinois kinesiology and community health professor Charles Hillman. “However, our current randomized, controlled trial should provide the most comprehensive assessment of this relationship to date.”
So what are the overall implications of this research? Megan Herting, a postdoctoral fellow with the division of research on Children, Youth, and Families at Children’s Hospital of Los Angeles, told Dotinga that it is hard to say at this point, as the research also revealed that kids with lower fitness levels also tended to weigh more.
“It is unclear if it is actually fitness or ‘fatness’ that may be affecting the brain. Studies show that individuals with obesity have different brains compared to their healthier-weight peers,” she said. “These findings do challenge that if you are aerobically fit, you are likely to be dumb. In fact, from an evolutionary perspective, we were made to move. So rather than fitness being ‘good’ for the brain and cognition, it is feasible that being sedentary may be ‘bad.’”
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