http://abcnews.go.com/sections/living/DailyNews/exercise990222.html
Exercise Helps Heart, Head The Usual, Plus It May Grow Brain Cells
W A S H I N G T O N, Feb. 22 — Two reports published today added to
the overwhelming body of evidence that exercise is crucial not only to
staying alive, but to boosting brain power as well.
A review of studies for the American Heart Association found that
regular, moderate exercise keeps blood pressure down, lowers cholesterol
and reduces the risk of blood clots that cause heart attacks. And a
study published in the journal Nature Neuroscience showed that mice who
engaged in regular exercise grew twice as many new brain cells as mice
who sat in their cages.
“The difference was striking,” Fred Gage, a neurologist at the Salk
Institute in La Jolla, California, said in a statement. “And because we
know now that human brains also make new cells, it just might be that
running or other vigorous exercise stimulates brain cell production in
people as well.”
Gage, a leading researcher into brain development, reported in November
that human brain cells do divide and grow, something that doctors did
not think could happen.
Conventional medical wisdom had held that the human brain is static —
once it is fully developed it cannot renew itself. Gage’s team showed
that belief was false. In April, Gage’s group showed that mice kept in
cages th tunnels, toys and an exercise wheel grew more brain
cells than bored mice. In the most recent study, the Salk team was
trying to discover just what kind of exercise was most important.
They kept the “control” group of mice stuck in ordinary cages, and a
“runner” group that of mice that were allowed to run as they pleased on
an exercise wheel.
Two other groups of mice were designated as “swimmers.” One group of
swimmers had to learn a maze, while the other was just put in a shallow
pool every day to swim. The runners still grew more new brain cells than
the swimmers.
“We don’t know if it’s the voluntary factor that’s key — that is, the
running mice were free to jump on or off the wheel as they liked — or if
it’s because the swimmers simply got less exercise,” Gage said.
Gage said he is not sure if the exercising mice with more new brain cell
growth also are smarter. “But it seems reasonable to think they might
be,” he said. “The new cell growth takes place in the part of the brain
called the hippocampus, which has been linked by many studies to
learning and memory. And the ‘enriched’ mice in previous studies
performed better on learning tests.”
Now the team is testing the mice to find out whether running directly
affects learning ability.
In the American Heart Association report, published in the group’s
journal Circulation, Dr. Roy Shephard of the University of Toronto and
Gary Balady of Boston University Medical Center performed an analysis of
100 different studies.
They found that all studies consistently show that moderate exercise —
enough to break a sweat — performed regularly can lower blood pressure,
reduce cholesterol, reduce the overall risk of heart disease and prevent
dangerous blood clots.
Exercise also helps people who have already suffered a heart attack or
heart disease, the review found. And the benefits can be seen day to
day. Patients have lower blood pressure on days they exercise than on
days they do not, one study found.
Copyright 1999 Reuters.
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Judith Richards, London, Ontario, Canada
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