Building the Mental Muscle
Date Published: Thursday, 13th May 2004
Source: ABC - Science Online


[This is the print version of story
http://www.abc.net.au/science/features/mentalmuscle/default.htm]

Worried about alzheimers? Concerned that your brain may be shrinking?
Staying sharp may be as simple as a spot of exercise - it seems that moving
your muscles does wonders for your brain power! And the good news is that
it's never too late to start. Elaine Mulcahy reports.

Staying physically fit throughout life can help you stay mentally fit.
Image: Reuters
The beneficial effects of exercise on the workings of the human brain have
long been known. Getting physical has been positively related to several
facets of mental health such as reduced stress, anxiety and depression, and
found to trigger elevated mood states and an overall sense of improved
well-being.


Phillip Tomporowski, an exercise scientist at the University of Georgia in
the US who studies the effects of exercise on the mind, says, "After a bout
of aerobic exercise you are more sensitive to changes in the world around
you, better able to make good decisions, and when you need to act, you're
quicker off the mark."

However, the enduring effects of endurance fitness and the extent to which
cardiovascular strength actually determines the brains capacity to survive
and strengthen in the longer-term has not been completely understood - until
now.

Training for smarts

Over the past number of years, a research team at the University of Illinois
in the US have completed an extensive study that specifically monitored the
relationship between cardiovascular fitness and a healthy brain in old age.
Their findings, soon to be published in the Proceedings of the National
Academy of Sciences (USA) reveal some staggering results.

They found that, not only does cardiovascular fitness lead to improved
performance on a wide range of mental tasks, but it also prevents the
breakdown of brain cells that typically occur with aging, reducing the
likelihood of a wide range of mental illnesses such as Alzheimer's disease.

In this test for attentional control and ability to reject conflicting
information, the participants were asked to determine the orientation of the
central arrow in a row of five arrows. In some cases the surrounding arrows
were facing in the opposite direction (top), which makes the task slightly
more difficult. In others all the arrows pointed in the same direction
(bottom).
The scientists first took a group of fit and not-so-fit adults, ranging in
age from 58 to 77, and tested them on a mental task that required them to
quickly identify the direction of an arrow (see figure on the right), which
was surrounded by other arrows that may or may not have been pointing in the
opposite direction. This task is considered by scientists to be a good
indicator of the ability to focus attention without being distracted or
confused by conflicting information - an ability that tends to diminish as
we get older.

The fitter participants did much better on the task than their un-fit
counterparts. They were faster at solving the test and were better able to
focus their attention. Brain scans also revealed that the older adults who
had good cardiovascular fitness also had greater activation in several areas
of the brain associated with attentional control and less activation in
regions of the brain that respond to conflict.

In a more detailed comparison of the brain scans, it was also found that
overall there was less shrinkage in the brains of the fit participants. In
normal aging, the human brain begins to breakdown when we reach our
thirties - we typically lose about 25 per cent of the connections between
our brain cells between the ages of 30 and 90 and most of this occurs in the
parts of the brain that deal with our most complex functions: problem
solving, memory, logic, and so on. But, the researchers found that these
areas of the brain that are most gravely affected by aging also showed the
most advantage of aerobic fitness and were more stable in adults with higher
cardiovascular fitness.


How so? rodents to the rescue

Scientists recently found that aerobic fitness tends to increase the levels
of important chemicals in rats' brains. Image: National Institute of General
Medical Sciences, USA
It is not entirely understood why staying physically fit could prolong the
life of the brain, and the neural mechanisms underlying the cognitive
improvements associated with cardiovascular fitness in aging adults has not
been very well studied in humans. It has, however, been studied in rats.

A group of scientists became aerobic fitness trainers to a group of rats for
a week and found that the training tended to increase the levels of
important chemicals produced in the rats' brains, most notably a chemical
called BDNF - brain-derived neurotrophin factor - which has an important
role in maintaining the overall strength of the brain through assisting in
increasing the supply of blood to different regions, enhancing the number of
connections between nerve cells, and perhaps most importantly, the
development of new brain cells.

In short, cardiovascular fitness seems to increase and strengthen the number
of connections between brain cells and enhance the brains blood supply. The
researchers say, "The end result is a brain that is more efficient and
adaptive, which translates to better learning and performance."

Never too late to get in shape

Cardiovascular exercise, like roller blading, prevents the breakdown of
brain cells that typically occur with aging. Image: Reuters
These findings are good news for all budding, blooming and blossoming
pensioners, but couch potatoes should not be disheartened because it seems
it is never too late to get that mental muscle back in shape.

To prove it, the researchers took their group of un-fit adults, who before
confessed to leading very sedentary lives, and put them on a training
program - half were put on a path to aerobic fitness, the rest embarked on a
"stretching, limbering, and toning for the whole body" class, much like yoga
or pilates.

After six months - three days a week - on the training programs it was found
that adults in the aerobic class not only significantly increased their
cardiovascular fitness, but also scored more than ten per cent higher on the
mental challenge tasks. The stretching class also improved on the tasks, but
only by two per cent.

Brain scans also showed that the adults in the aerobic class had much
greater activation in regions of the brain known to be involved in complex
functioning than they did before they started the program, whereas the
stretching and toning group stayed pretty much the same as before.

Stan Colcombe the lead author of the study has one word for people:
"EXERCISE!" He says, "I tell all of my older family members to get out and
do a little bit every day," the benefits go way beyond physical health and
fitness.

Keep it friendly

Stretching classes like yoga and pilates help participants with mental
challenges. Image: Reuters
Another important aspect of visiting the local swimming pool or golf course
is the social side, which can sometimes be just as important for older
adults. This too can be good for the mind.

A recent study published in the Journal of Epidemiology and Public Health
reported that taking part in a range of activities that require a high level
of concentration or social interaction can improve a person's ability in a
variety of cognitive tests, such as verbal memory, mathematical reasoning,
vocabulary and verbal fluency.

Melbourne Super Gran, Janet Bennett, organises a cycling group in Melbourne
called COTA (Council of the aging) Cycling. Their usual fortnightly ride is
anywhere between forty and sixty kilometres. The social side can be just as
important for many of the riders as keeping fit, Janet says, "The group are
very keen to have a coffee stop on every ride as well as enjoy a picnic
lunch together. Any newcomers usually comment to me about what a friendly
group it is." Friendly and smart, we can assume!

More about Exercise from ABC News in Science


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Published May 13, 2004



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