walking is good for the brain

Earlier this year, researchers at Stanford University reported the results of a 21-year study that tracked more than 500 runners who were in their 50s or 60s, and are now in their 70s and 80s.

The joggers, who put in an average of 4 hours a week on the trail, were matched for comparison with an otherwise similar group of people who did not run.

Nineteen years into the study, 34 percent of the non-runners had died, versus 15 percent of the runners.

Of course, time still caught up with the runners -- with many of them reporting disability such as difficulty dressing or grooming or getting out of a chair. But on average, runners' initial report of a disability came 16 years later than that reported by the non-runners on annual questionnaires.

But for the brain, walking may actually be better than running, since there's more oxygen left in the blood to reach the brain than from most vigorous exercise. Studies in the elderly have found that stroke risk can be cut by as much as 57 percent in those who walked as little as 20 minutes a day.

Another study of older women found that those who walked 17 miles or more a week were about 40 percent less likely to experience mental decline than those who walked a half mile or less a week.

.. another study just published in December in the journal Psychological Science, suggests that where we walk may be as important as how much when it comes to brain benefits.

Researchers at the University of Michigan ran two experiments with a group of volunteers, testing them for memory and attention, then sending them out on a walk either in a park or through downtown Ann Arbor, then back for a re-test.

Performance on the memory and attention test improved greatly for the group that took a walk in the park, but did not improve for the group that walked downtown. A similar result was seen when the two groups sat for a while and viewed photos of nature or urban scenes.

The scientists suspect that walking around an urban setting presents the brain with a relatively complex, even confusing pattern of stimulation, while a walk down a tree-lined path takes less mental effort and has a more restorative effect for the brain's attention centers.