Scientists from the Harvard School of Public
Health, University of Pittsburgh and University of Southern
California are finding that exercise might offer a powerful
shield against Parkinson's. Their studies suggest physical
activity might help protect neurons in the brain from
the ongoing damage of Parkinson's.
"I do believe that exercise will
slow the progression," says Michael Zigmond, a neurologist
at the University of Pittsburgh's Institute for Neurodegenerative
Disorders.
The findings, based on research first
on lab animals and now on humans, suggest lifestyle measures
could prevent or control a disease that afflicts an estimated
1 million people in the USA. It's a number that will rise
in the coming decades as boomers start to develop the
disease, which usually strikes after age 50.
But Parkinson's also can hit people
in their prime. Actor Michael J. Fox was just 30 when
he got his diagnosis in 1991.
Sixty-one year old John Ball says
he was in his late 20s when he experienced his first symptom,
but he didn't get an official diagnosis until age 39.
By that time, the disease already had damaged the substantia
nigra and other key brain regions. An injury to cells
in those regions causes a shortage of a brain chemical
called dopamine, which leads to difficulty in controlling
movement.
Drugs treat the symptoms, but they
cannot stop or slow the progression of the disease, says
Robin Elliott of the Parkinson's Disease Foundation in
New York. Yet studies have suggested that a daily jog
might do what modern medicine cannot.
"There is no cure for this disease,
so neuroprotection would be a very big deal," Elliott
says.
The evidence on Parkinson's and exercise
includes:
• A study in 2005 by Alberto
Ascherio at the Harvard School of Public Health in Boston.
Researchers found that men who said they jogged, played
basketball or did some other sweat-breaking activity at
least twice a week as young adults reduced their risk
of getting Parkinson's later by 60%.
• Zigmond and his colleagues
at the University of Pittsburgh found that exercise offered
rats a powerful shield against a Parkinson's-like disease.
These rats were injected with a toxin that kills brain
cells, yet they never developed symptoms and had almost
no sign of damage to the brain, including to the dopamine-producing
neurons.
"Exercise almost completely protected
against the loss of these neurons," Zigmond says.
At the Society for Neuroscience meeting
held in Washington, D.C., in November, Zigmond's team
presented evidence suggesting that the benefit comes from
the production of chemicals called neurotrophic factors.
Exercise seems to spur certain brain cells to release
these chemicals, which then protect brain cells damaged
by the Parkinson's disease process. That and other evidence
indicates that exercise might help even people who already
have the disease.
For example, studies by Beth Fisher
and Michael Jakowec at the University of Southern California-Los
Angeles suggest that mice that work out on a treadmill
after getting a Parkinson's-like disease still benefited.
The mice already have brain damage, but the findings suggest
that exercise might help repair or compensate for the
damage.
Exercise helped these mice function
at near-normal levels. "They ran almost as fast on the
treadmill as normal mice," Jakowec says.
Other research suggests physical
activity might do the same for humans. In a preliminary
study of 19 people, researcher Anthony Delitto at the
University of Pittsburgh found that patients who exercised
as little as three times a week showed improvements in
balance and the ability to perform daily tasks.
Those findings need to be verified
in larger studies, but exercise, especially if combined
with next-generation drugs, might be able to ward off
the increasing disability that goes along with the disease.
"While exercise probably isn't a
cure, it's probably going to be an important part of a
cure," Fisher says.
Still, the literature is replete
with studies on rats that have gone bust when researchers
try to replicate the findings in large-scale human trials.
But the scientific uncertainties don't affect the practical
implications of the research, experts say.
"Exercise is not going to hurt you,"
Zigmond says. "If we were talking about a drug, I'd say
wait. But there are no side effects to working out."
The Harvard study indicates regular
workouts early in life might help keep the brain free
of damage that can lead to Parkinson's. People who are
healthy now are advised to build a fitness routine into
their daily schedule. Play basketball. Go out for a walk.
Swim laps.
The advice is much the same for people
who have the disease. Experts say running, walking and
other activities all help build muscle mass, which is
a boon for people who are fighting not just the disease
but also the loss of muscle power that comes with old
age.
Exercise gives people with Parkinson's
more strength and balance, Delitto says. Fitter patients
are better able to perform daily tasks that can help keep
them independent.
Ball says he doesn't know whether
the research on neuroprotection will pan out. Yet he says
his fitness routine, which includes training runs, bike
riding and playing golf, helps him in very practical ways.
"When I'm in good shape, I have more resources to draw
from," he says. "It's nice to have that strength."
Ball retired from his job as manager
for Honda at age 58. Now, together with his wife, Edna,
he co-chairs Team Parkinson, a non-profit that raises
money to fund Parkinson's research.
He has run many marathons, but he
has to time his medication so that it won't wear off.
Sinemet, a drug converted to dopamine in the body, can
stop working. If that happens in the middle of a race,
Ball will start to stumble, shake and look every bit the
image of an older man with Parkinson's.
At times, he has had to be half-carried
across the finish line. What keeps him going?
Ball says running gives him the courage
to face the future, a future that will be filled with
the declines of old age and advancing Parkinson's disease
no matter what he does.
And he runs for another powerful
reason, one that experts say is very important for people
who want to keep up a fitness routine: He loves to run.
"The things that are important to
you," he says, "the things that bring joy to your life,
you've just got to find a way to do them."
