Gretchen Reynolds from the New York Times writes excellent articles about exercise and health. In this recap of 2015 she reviews several articles associating exercise with better brain function, especially as we age.
The one study that stood out, however, was looking at twins. The study found that the twin with stronger leg muscles had greater brain volume. As the mother of twins, I find this very interesting. As a mom, I offer my twins the same foods and the same opportunities for exercise and sports, however, they do not necessarily take advantage of these opportunities in the same way or at the same rate.