Taking a regular, daily walk is good for physical health, and now it appears that it may slow the progression of Alzheimer's disease and ward off mental decline as well. The amount of walking needed to realize these benefits to the brain is more than just a stroll around the block: researchers from the University of Pittsburgh concluded that to guard against cognitive decline you've got to put in an average of at least five miles a week, every week, for about 10 years. The investigators analyzed data from an ongoing 20 year study looking at the weekly walking patterns among 426 seniors. At the start of the study, 44 of the participants already had Alzheimer's and another 83 had mild cognitive impairment (in half of all cases, this disorder eventually progresses to Alzheimer's). All the others were cognitively healthy. Ten years into the study, after accounting for age, gender, body-fat composition, head size and education level, the researchers found that brain volume was largest among participants who exercised the most (greater brain volume is a sign of general brain health and less brain cell death). What's more, walking five miles a week appeared to protect those with some form of cognitive impairment against further cognitive decline. The healthy participants had to walk six miles a week to protect their brain health.
