A new study from Kings College London has indicated that strong legs have a direct correlation to a healthy brain, as discussed in this New York Times Well article.
The reason that this study is so valuable is because it was conducted on 324 twins (or, I guess you could say, 162 sets of twins). Twins typically share the same early home environment and many of the same genes, and if they are identical, then of course all their genes are the same. So if one twin’s body, brain and thinking abilities begin to differ substantially over the years from the other’s, the cause is less likely to be solely genetic or the early environment, and more likely to be attributable to lifestyle, including exercise habits.
The legs are the largest and most powerful muscles in the body. Older Adults with more powerful leg muscles get around easier than those with weaker leg muscles; have less falls or accidents; and also tend to have sharper minds, studies such as this one have shown. This study found that those who had the sturdiest legs a decade ago showed the least deterioration in thinking skills, even with controlled factors such as fatty diets, high blood pressure and shaky blood-sugar control. If one genetically identical twin had had sturdier legs than the other at the start of the study, she now displayed significantly more brain volume and fewer “empty spaces in the brain” than her weaker sister. So, over all, among both the identical and fraternal twins, fitter legs were strongly linked, 10 years later, to fitter brains. There really is no downside to fitness!
The take home message should be that building muscles, especially your leg muscles could strengthen your mind. If you are not currently doing any exercise to build your leg muscles, you might want to consider walking, running, standing, cycling or dancing more often. The brain needs exercise to keep fit and young!