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(Wolfville,
NS) - Older men and women who performed moderate
resistance exercise at home 30 minutes a day, three times a week,
for eleven months, showed a significant increase in natural killer
cell activity, the immune system's first line of defense against
viral infection, according to a study by researchers at Acadia
University in Nova Scotia. The sustained exercise may be the key,
say the researchers, since earlier studies using shorter periods of
up to three months did not find this significant increase in immune
system activity with resistance training.
In addition to
enhanced immune response, the adults also showed significant
improvements in muscle strength and lipid profiles, with decreased
total cholesterol and LDL concentrations.
Jennifer DiPenta, a
student working in the labs of Dr. René J. L. Murphy and Dr. Julia
Green-Johnson, reported the study at Experimental Biology 2004, as
part of the scientific sessions of The American Physiological
Society.
Baseline immunological
and physiological functions as well as lipid profiles were obtained
from 10 men and 12 women, ages 54 to 82 years (median age 63.5), all
retired. They then were trained in simple, moderate intensity
resistance exercises, involving tubing and exercise balls, which
they could do alone at home. During the next eleven months, the
participants were monitored with bi-weekly phone calls and monthly
home visits, during which the programs were altered, based on their
abilities. At the end of approximately 11 months of training, they
returned to the Centre of Lifestyle Studies at Acadia University for
another series of physical and immune function tests.
Muscle strength
increased significantly. There were no changes in weight, but total
cholesterol and plasma LDL decreased significantly (HDL remained
unchanged). To measure immune activity, lymphocytes from each
participant were incubated with K562 tumor cells known to be
targeted by natural killer cells. After eleven months of
participating in the study, the participants showed a higher
response.
Dr. Green-Johnson
says, "It was gratifying to see the improvement in these older
people in ways that should enable them to maintain their health and
independence with advancing age." Dr. Murphy adds, "We believe the
take-home message is that there are several important health
benefits for older people who choose to participate in a simple
home-based exercise program."
The study was funded
by the Nova Scotia Health Research Foundation, and the exercise
equipment was provided by Theraband. Ms. DiPenta holds a fellowship
provided by The American Physiological Society.
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