Walking Correlates With Brain Volume, Cognitive Ability

Clearly.

Seniors committed to walking had larger gray-matter volume and less cognitive impairment years later than those with more sedentary habits, researchers said.

Among 299 cognitively normal participants in the large Cardiovascular Health Study, those in the top quartile of distance walked each week at baseline had markedly higher gray-matter volumes when measured by MRI nine years later compared with participants in the lower three quartiles, according to Kirk Erickson, PhD, of the University of Pittsburgh, and colleagues.

That's gotta be it.