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 “The current findings suggest that maintaining high fitness in
midlife may boost brain health on average 20 years later in adults
who have not yet experienced cognitive impairment,” lead study
author Qu Tian, a gerontology researcher at the U.S. National
Institute on Aging, said by email.
Tian and colleagues followed 146 older adults over a decade, using
treadmill tests to measure cardiorespiratory fitness. They also used
magnetic resonance imaging (MRI) to detect changes in brain volume.
At the start of the study in 1994, participants were 69 years old on
average. To be included, they had to be healthy and free of
cognitive impairment, dementia, Parkinson’s disease or other
neurological problems and have no history of stroke, heart or lung
disease, or cancer.
In the treadmill tests at the start of the study, researchers used
mathematical models to estimate participants’ fitness levels when
they were age 50.
People who were fitter at 50 had greater brain volume later in life
in the middle temporal gyrus, believed to be involved in memory,
language and visual perception, as well as in the perirhinal cortex,
thought to aid unconscious memory and object recognition. They also
had a greater volume of white matter; when this declines, it may be
an early symptom of Alzheimer’s disease.
Slower shrinking of two parts of the cerebral cortex region of the
brain, the middle frontal and angular gyri, may predict better
cardiorespiratory fitness in advanced old age, the researchers
report in the Journals of Gerontology, available online now.
The findings add to a growing body of evidence linking physical
exercise to higher volumes in certain areas of the brain, but
because long-term studies like this tend to attract healthier and
better-educated people, it’s hard to say whether the results would
be similar for a broader population, said Sandra Bond Chapman,
founder and director of the Center for BrainHealth at the University
of Texas at Dallas, who wasn’t involved in the study.
Moreover, not all people achieve the same gains in cardiorespiratory
fitness from the same amount of exercise, and scientists aren’t sure
how cardiorespiratory fitness relates to cognitive function, Chapman
said by email.
It’s also hard to distinguish between cause and effect in the study,
said Dr. Jeff Burns, director of the Alzheimer and Memory Clinic at
the University of Kansas Medical Center in Kansas City.
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“A challenging question that is hard to get to the root of is
whether exercise makes us smarter or do smarter people tend to
exercise more than others,” Burns, who wasn’t involved in the study,
said by email.
While the current study focused on how cardiorespiratory fitness can
improve brain volume, previous research has linked this type of
fitness to improved memory for names or specific events, as well as
planning and the ability to switch between tasks, Scott Hayes,
Associate Director of the Neuroimaging Research for Veterans Center
at the VA Boston Healthcare System, who also didn't work on the
study, told Reuters Health by email.
More research is still needed in larger groups of people to better
understand the effect of cardiorespiratory fitness on the brain,
commented Kirk Erickson, a researcher at the Brain Aging & Cognitive
Health Lab at the University of Pittsburgh, who wasn't involved in
the current project.
“Nonetheless," Erickson said by email, "this study adds to a field
that has been repeatedly showing positive associations and effects
of physical activity and fitness on brain health in late adulthood.”
SOURCE: http://bit.ly/1J5BxBL
J Gerontol Series A 2015.
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