Children who exercise regularly also tend to do better in math. Until now, little research existed to explain this relationship, but a team of scientists at the University of Illinois at Urbana-Champaign has made a major discovery: aerobic fitness results in a thinner layer of gray matter in the brains of young children. This difference in brain structure, they propose, leads to better cognitive control and working memory, key skills related to math ability.
What about reading? The researchers found no correlation between fitness and reading, but they're hoping that future studies can shed more light on the subject.
Research Cited: Chaddock-Heyman, L., Erickson, K. I., Kienzler, C., King, M., Pontifex, M. B., Raine, L. B., Hillman, C. H., & Kramer, A. F. (2015). The Role of Aerobic Fitness in Cortical Thickness and Mathematics Achievement in Preadolescent Children. PloS one, 10(8), e0134115.