Small amount of exercise could protect
against memory loss in elderly, CU study
suggests
August 15, 2011]--A new University of
Colorado Boulder study shows that a small
amount of physical exercise could profoundly
protect the elderly from long-term memory
loss that can happen suddenly following
infection, illnesses or injury in old age.
In the study, CU-Boulder Research Associate
Ruth Barrientos and her colleagues showed
that aging rats that ran just over half a
kilometer each week were protected against
infection-induced memory loss.
"Our research shows that a small amount of
physical exercise by late middle-aged rats
profoundly protects against exaggerated
inflammation in the brain and long-lasting
memory impairments that follow a serious
bacterial infection," said Barrientos of the
psychology and neuroscience department.
The results of the study will appear in the
Aug. 10 edition of The Journal of
Neuroscience.
"Strikingly, this small amount of running
was sufficient to confer robust benefits for
those that ran over those that did not run,"
Barrientos said. "This is an important
finding because those of advanced age are
more vulnerable to memory impairments
following immune challenges such as
bacterial infections or surgery. With baby
boomers currently at retirement age, the
risk of diminished memory function in this
population is of great concern. Thus,
effective noninvasive therapies are of
substantial clinical value."
Past research has shown that exercise in
humans protects against declines in
cognitive function associated with aging and
protects against dementia. Researchers also
have shown that dementia is often preceded
by bacterial infections, such as pneumonia,
or other immune challenges.
"To the best of our knowledge, this is the
first study to show that voluntary exercise
in rats reduces aging-induced susceptibility
to the cognitive impairments that follow a
bacterial infection, and the processes
thought to underlie these impairments,"
Barrientos said.
In the study, the researchers found that
rats infected with E. coli bacteria
experienced detrimental effects on the
hippocampus, an area of the brain that
mediates learning and memory.
Previous research has shown that immune
cells of the brain, called microglia, become
more reactive with age. When the older rats
in the study encountered a bacterial
infection, these immune cells released
inflammatory molecules called cytokines in
an exaggerated and prolonged manner.
"In the current study we found that small
amounts of voluntary exercise prevented the
priming of microglia, the exaggerated
inflammation in the brain, and the decrease
of growth factors," Barrientos said.
The next step of this research is to examine
the role that stress hormones may play in
sensitizing microglia, and whether physical
exercise slows these hormones in older rats,
she said.
