Walking 6 to 9 Miles a Week May Help Save
WEDNESDAY, Oct. 13 (HealthDay News) -- Walking about six miles a
week appears to protect against brain shrinkage in old age, which
in turn helps stem the onset of memory problems and cognitive
decline, new research reveals.
"We have always been in search of the drug or the magic pill to help treat brain disorders," noted Kirk I. Erickson, an assistant professor of psychology at the University of Pittsburgh and the study's lead author. "But really what we are after may be, at least partially, even simpler than that. Just by walking regularly, and so maintaining a little bit of moderate physical activity, you can reduce your likelihood of developing Alzheimer's disease and [can] spare brain tissue."
A report on the research, which was supported by the U.S.
National Institute on Aging, is published online Oct. 13 in
Erickson and his colleagues began tracking the physical activity
and cognitive (or thinking) patterns of nearly 300 adults in 1989.
At the start, all participants were in good cognitive health, they
averaged 78 years old and about two-thirds were women. The
researchers charted how many blocks each person walked in a
Nine years later, they were given a high-resolution MRI scan to
measure brain size. All were deemed to be "cognitively normal."
But four years after that, testing showed that a little more
than one-third of the participants had developed mild cognitive
impairment or dementia.
By correlating cognitive health, brain scans and walking
patterns, the research team found that being more physically active
appeared to marginally lower the risk for developing cognitive
But more specifically, they concluded that the more someone
walks, the more gray matter tissue the person will have a decade or
more down the road in regions of the brain -- namely the
hippocampus, the inferior frontal gyrus and the supplementary motor
area -- that are central to cognition.
And among the more physically active participants who had
retained more gray matter a decade out, the chances of developing
cognitive impairment were cut in half, the study found.
However, the researchers stressed that the relationship between
walking and gray matter volume appears to apply only to people who
regularly walk relatively long distances that equal about six to
nine miles a week.
Walking more than the six- to nine-mile range, however, did not
have cognitive benefit, the study found.
"That's because the size of our brain regions can only be so large," Erickson said, adding that the opposite isn't true. "So with no exercise, there can be significant deterioration and decay with age."
However, he added, "what we often tend to think of as an
inevitable component or characteristic of aging -- memory decline
and brain decay -- is clearly not inevitable. There's plenty of
evidence now, and this study is part of that, that shows that we
can retain our brain tissue and retain our memories well into late
adulthood by maintaining an active and engaged lifestyle."
Dr. Steven V. Pacia, chief of neurology at Lenox Hill Hospital
in New York City, described the study's finding as both
"intriguing" and an "undoubtedly positive message to send to the
"My first reaction to studies like this is that only in America do we have to prove to people that it's good to walk," he said with a chuckle.
"But it stands to reason that being active as we age is going to have a beneficial effect on the brain, just as being inactive is going to have a negative impact," Pacia noted. "Because the brain lives in the environment of the body."
But there may be a catch. "This is just an observational study,"
Pacia noted. "And while we may assume that the relationship between
the brain and activity is a prevention-of-atrophy issue -- just
like it is with muscle and bone -- this study doesn't actually
prove that. We don't yet know enough about the use-it-or-lose-it
notion with respect to brain and exercise. So we do need more
research to look at that."
The U.S. National Institute on Aging has more on
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