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Exercise sharpens focus, decision-making among aging adults
Jim
Barlow, Life Sciences Editor
217-333-5802; jebarlow@illinois.edu
2/16/2004
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CHAMPAIGN,
Ill. — Aging
adults who give up a sedentary lifestyle and replace it with a cardiovascular
fitness regimen as simple as brisk walks reap greater focus and reduced
decision-making conflict as they perform a variety of tasks, scientists
say.
That conclusion comes from a study that utilized functional magnetic
resonance imaging to measure changes in brain activity in adults ranging
in age from 58 to 78 before and after a six-month program of aerobic
exercise. The study, done at the University of Illinois at Urbana-Champaign,
appears on line this week ahead of print publication in the Proceedings
of the National Academy of Sciences.
Scientists, led by Arthur F. Kramer, a professor of psychology and researcher at the Beckman
Institute for Advanced Science and Technology at Illinois, identified
specific functional differences in the middle-frontal and superior parietal
regions of the brain that changed with improved aerobic fitness. These
changes allowed researchers to predict improvements in performance on
a decision-making task.
The middle-frontal region of the brain is responsible for keeping goals
of an activity in focus. The superior parietal area has been linked
to many functions, including the spatial attention.
Participants of the aerobic-exercise intervention reduced their level
of behavioral conflict in completing a computer-based task by 11 percent
from pre-exercise levels, while the control subjects who performed stretching
and toning activities achieved a statistically insignificant decrease
of 2 percent.
Previously, Kramer and colleagues had documented that aging adults do
better cognitively if they are physically fit and that parts of the
brain in active older people contain more white and gray matter.
The new study – the first involving an exercise intervention in
human subjects along with state-of-the-art neuroimaging – focused
on actual changes in brain function and the capability of previously
non-active aging adults to improve their ability to ignore distractions.
It ties brain changes to cognitive changes, Kramer said.
"We continue to find a number of cognitive benefits in the aerobic
group that are very consistent with results found in the animal literature,"
he said. "The brain circuits that underlie our ability to think
– in this case to attend selectively to information in the environment
– can change in a way that is conducive to better performance
on tasks as a result of fitness. The kinds of tasks that we explored
are similar to those encountered in real world situations such as driving
a vehicle or any endeavor that requires a person to pay attention despite
distractions."
Results of aerobic-intervention programs in rats and mice regularly
show biochemical changes, particularly in the production of a molecule
known as brain-derived neurotropin factor, which serves to protect the
brain and increase the connections between neurons and promote neurogenesis,
he said.
The new paper looked at brain function of subjects with differing fitness
levels at the beginning and end of each experiment. Participants doing
toning and stretching had increased activation in some areas of the
brain but not in those tied to better performance.
The aerobic exercise used in the study involved gradually increasing
periods of walking over three months. For the final three months of
the intervention program, each subject walked briskly for 45 minutes
in three sessions each week.
The National Institute on Aging and the Institute for the Study of Aging
funded the study. Co-authors were postdoctoral researcher Stanley J.
Colcombe; Edward McAuley, professor of kinesiology; Neal J. Cohen, professor
of psychology; Andrew Webb, professor of electrical and computer engineering;
and doctoral students Kirk I. Erickson, Paige Scalf, Gerry J. Jerome,
David X. Marquez and Steriani Elavsky.
