Photo credit: Benjamin Brink, The Oregonian
So, according to a pilot study done in Seattle, vigorous aerobic exercise seems to slow the progress of Alzheimer's Disease. They don't know if it will prevent it, and it doesn't cure it, but it does seem to improve mental function in those on the road to brain fade. Abstract here.
Going outside once in a while also seem to have an affect on vision. Latest in that arena points out that myopia seems to develop less in children who go outside, and that this makes more difference than watching TV, reading, or video games when it comes to turning little Johnny into a squinter.