Walking helps prevent brain atrophy and dementia

Not only does walking for exercise have favorable metabolic and hormonal effects; a study just published in the journal Neurology provides evidence that it is a beneficial stimulus to the brain. The authors state:

"Here we tested whether PA [physical activity] would be associated with greater gray matter volume after a 9-year follow-up, a threshold could be identified for the amount of walking necessary to spare gray matter volume, and greater gray matter volume associated with PA would be associated with a reduced risk for cognitive impairment 13 years after the PA evaluation."

They examined 299 adults for the the association between gray matter volume, physical activity (quantified as the number of blocks walked per week), and cognitive impairment. After 9 years high-resolution brain scans were acquired. Examination for cognitive impairment was done 13 years after the start of the study. What did the data show?

"Greater PA predicted greater volumes of frontal, occipital, entorhinal, and hippocampal regions 9 years later. Walking 72 blocks [per week] was necessary to detect increased gray matter volume but walking more than 72 blocks did not spare additional volume. Greater gray matter volume with PA reduced the risk for cognitive impairment 2-fold."

The authors summarized the evidence by concluding:

"Greater amounts of walking are associated with greater gray matter volume, which is in turn associated with a reduced risk of cognitive impairment."