Research
Boost Immune System
Scientists Focusing On How Exercise Raises Immunity
7-7-2003
CHAMPAIGN, Ill. -- An increasing number of doctors and other
health experts have been encouraging older adults to rise
from their recliners and go for a walk, a bike ride, a swim,
or engage in just about any other form of physical activity
as a defense against the potentially harmful health consequences
of a sedentary lifestyle.
"Exercise
is touted as a panacea for older adults," said Jeffrey
Woods, a kinesiology professor at the University of Illinois
at Urbana-Champaign, who noted that fitness programs are
routinely recommended for people with various health problems
-- from diabetes to heart disease.
Health
experts generally recognize that this population benefits
from physical fitness, he said. What they don't know is
why exercise appears to have certain preventive and restorative
health effects. Also unknown is what -- if any -- relationship
exists between exercise and immune functioning.
"Despite
the numerous benefits of exercise -- for example, improving
cardiovascular and muscular fitness -- we know very little
about how exercise affects the immune systems of older adults,"
Woods said. "Good, bad or indifferent, this information
could have important public health consequences for our
aging population." For that reason, Woods and colleagues
in the university's kinesiology department are conducting
research that seeks to establish the link between exercise
training and immune function. The field, he said, is still
in its infancy, with Illinois researchers among those who
are defining it.
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"Our laboratory is using both animal and human
models to address the extent to which exercise affects immune functioning
and susceptibility to infectious disease in older populations,"
Woods said. "We have obtained some exciting preliminary data
in mice that suggest that moderate exercise or training may boost
some immune function measures and reduce mortality caused by influenza.
While we don't have corollary evidence yet in people, we are in the
midst of conducting a large clinical exercise trial in older adults,
funded by the National Institute on Aging, that will provide definitive
evidence as to whether moderate exercise training influences immune
function."
In the meantime, results of one study conducted in
Woods' lab, published in the current online edition of the journal
Brain, Behavior and Immunity, indicates that exercise training increases
the ratio of naïve T cells to memory T cells in the spleens of
older mice. The finding is potentially significant, he said, because,
on this measure, "we turn old mice into young mice." When
people and animals age, he explained, the thymus, which produces naïve
T lymphocytes, shrinks, thus producing fewer naïve cells. "This
is one reason that older people/animals have trouble responding to
new environmental pathogens."
And with the recent appearance of so many new environmental
pathogens -- from West Nile Virus to SARS and monkeypox -- Woods said
the ability to boost the immune systems of the elderly, who are among
the populations most at risk from infection, is a worthy goal.
This
story has been adapted from a news release issued by University Of
Illinois At Urbana-Champaign, www.uiuc.edu.
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