Exercise your body, save your brain

Can walking three times a week save your memory?   According to the wellness blog Healthy Fellow, yes.
A study published in Journal of the American Medical Association (PMID: 18768421) found that 3 50-minute sessions per week of moderate exercise helped people with memory problems (not diagnosed with Alzheimer's or dementia).  After six months, the exercise group did better on memory tests, had better memory retention, and their Clinical Dementia Rating (CDR) was lower (lower is better).
Another study showed that the more you exercise, the bigger your brain is.  (Mine must be huge, some weeks I get in 9 hours in the pool!)  Studying actual AD patients, the researchers found that those who "weren't physically fit" had four times more brain shrinkage than those who were. 
My dad walked every day and his brain was the size of a walnut.  I guess if he hadn't walked he would have died a lot sooner.