Perhaps you've noticed you're less likely to forget where you parked
your car after a brisk tennis match than after a trip to the library. There's a
reason for that, says a new study: in healthy seniors and those with emerging
memory problems, even a single brief bout of vigorous exercise and the release
of norepinephrine that comes with it can enhance memory of what came just
before it.
A new study finds that even a brief bout of exercise can improve seniors' memory. (Los Angeles Times / March 8, 2007)
The phenomenon is one of evolution's cleverest memory-enhancing tricks:
when an event triggers high emotion -- the unexpected sight of a snake, for
instance, and the fear reaction that comes with it -- we tend to remember
longer and better the details surrounding that event. For the young and
inexperienced, the ability to remember those details -- where and when one saw
that snake, and how exactly it behaved -- increases the odds that one will live
long enough to reproduce. But do those who have already survived into old age
also benefit from the norepinephrine effect, and can it help compensate for
memory impairment? Researchers at UC Irvine set out to explore those questions.
To do so, they recruited 31 healthy older adults with an average age of
69, and 23 subjects who had been diagnosed with "amnestic" mild
cognitive impairment -- memory loss that is problematic but which falls short
of Alzheimer's disease. All were shown a series of 20 emotionally positive
images -- beautiful landscapes, baby animals, sports scenes. And then, half of
those in each group were put on treadmills to exercise for six minutes at 70%
of their aerobic maximum. Subjects in the other half of each group were allowed
to sit quietly.
Sixty minutes after their brief workout (or their restful sit), the
subjects were given a surprise free-recall test, in which they were asked to
describe the photos they had seen and as many details as they could remember. Among
those with normal memory function, a single bout of exercise increased recall
of photos and details by 30%. Among subjects with amnestic mild cognitive
impairment, those in the brief-exercise group improved their recall even more:
they remembered twice the number of photos and details than did those who did
not exercise. They didn't remember as much as the non-exercising adults with
normal memory, but they did recall more than they would have. Not only did those with cognitive impairment improve their recall, they
released more norepinephrine in response to exercise, apparently compensating
for their faulty memories.
Sabrina Segal, a post-doctoral fellow at UC Irvine's Center for Stress
and Health and the study's lead author, said that researchers have established
that ongoing exercise regimens help support memory function in both healthy
older adults and those with memory problems. But she and her colleagues were
struck that for both groups, even a short, one-time bout of exercise -- a brisk
walk around the block, for instance -- strengthened recall for information
taken in just before. The study was published this week in the Journal of Alzheimer's Disease.
Source: Chicago Tribune
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