SEATTLE, Oct. 26 /PRNewswire/ -- Postmenopausal women who want to
decrease their risk of colds would be well advised to dust off their
sneakers and get moving, suggests a new study led by researchers at Fred
Hutchinson Cancer Research Center.
Through the first randomized clinical trial to investigate the impact
of moderate physical activity on common-cold incidence, Cornelia (Neli)
Ulrich, Ph.D., and colleagues found that postmenopausal women who exercised
regularly for a year had about half the risk of colds compared to those who
did not work out routinely. The findings appear in the November issue of
The American Journal of Medicine.
"This adds another good reason to put exercise on your to-do list,
especially now that cold season is here," said Ulrich, the paper's senior
author and an associate member of the Hutchinson Center's Public Health
Sciences Division. However, Ulrich is quick to point out that regular
exercise in moderation -- such as 30 to 45 minutes of brisk walking each
day -- is the key; other studies have shown that excessive, exhaustive
exercise can deplete immune function and increase the risk of colds.
The researchers found that the ability of moderate exercise to ward off
colds seemed to increase over time. "The enhanced immunity was strongest in
the final quarter of the year-long exercise intervention," Ulrich said.
"This suggests that when it comes to preventing colds, it's really
important to stick with exercise long term." Overall, the non-exercisers
experienced about twice as many colds as the exercisers, but in the last
three months of the intervention, the non-exercisers had a threefold
greater chance of coming down with colds.
The yearlong study involved 115 previously sedentary, overweight,
postmenopausal Seattle-area women. None smoked or took hormone-replacement
therapy. Half were randomly assigned to a moderate-intensity,
aerobic-exercise group and half, who served as a comparison group, attended
a weekly stretching class.
While the members of the exercise group were asked to work out at home
and at a gym for 45 minutes a day, five days a week, in fact they achieved
an average of about 30 minutes of exercise per day. "They were supposed to
do a little more exercise, but even so, we found it was enough activity to
boost immune function in the long run," Ulrich said.
Brisk walking was the activity of choice, accounting for 52 percent of
gym-based and 74 percent of home-based exercise. "It's been shown that just
a 30-minute walk can increase levels of leukocytes, which are part of the
family of immune cells that fight infection," Ulrich said, referring to a
possible biological explanation for the protective effect.
A major strength of this study was its yearlong duration, large number
of participants and randomized, controlled, clinical-trial design,
considered the gold standard of study designs in medicine.
Even though the study was larger and longer than others that have
addressed the impact of exercise on the risk of colds and upper-respiratory
infections, it still may not have had enough participants or followed them
long enough to provide a definitive answer, cautioned first author Jessica
Chubak, a research associate at the Hutchinson Center. "It would be
interesting to see what would happen over the course of a longer exercise
intervention," she said.
The overall goal of the study, funded by the National Cancer Institute,
was to assess the impact of physical activity on markers of breast-cancer
risk. In addition to reducing their incidence of colds, the women in the
exercise group also achieved significant reductions in weight, total-body
fat and intra-abdominal fat.
In addition to Ulrich, Chubak and colleagues at the Hutchinson Center,
collaborators on the study also included investigators from the University
of Washington, University of Alberta and University of New Mexico.
According to the National Institute of Allergy and Infectious Diseases,
Americans suffer an estimated 1 billion colds per year, resulting in a
leading cause of doctor visits and missed days from work and school. Adults
in the United States report an average of two to four colds per year.
About Fred Hutchinson Cancer Research Center -- The Hutchinson Center's
interdisciplinary teams of world-renowned scientists and humanitarians work
together to prevent, diagnose and treat cancer, HIV/AIDS and other
diseases. Center researchers, including three Nobel laureates, bring a
relentless pursuit and passion for health, knowledge and hope to their work
and to the world. For more information, please visit fhcrc.org.
About The American Journal of Medicine -- Known as the "Green Journal,"
The American Journal of Medicine ( http://www.amjmed.com ) is one of the oldest
and most prestigious general internal medicine journals published in the
United States. It is the official journal of the Association of Professors
of Medicine, a group comprised of chairs of departments of internal
medicine at more than 125 U.S. medical schools. The journal is published by
Elsevier.
CONTACT
Kristen Woodward
(206) 667-5095
kwoodwar@fhcrc.org
SOURCE Fred Hutchinson Cancer Research Center
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Related links:
http://www.fhcrc.org
http://www.amjmed.com
CONTACT:
Kristen Woodward of Fred Hutchinson Cancer
Research Center, +1-206-667-5095, or kwoodwar@fhcrc.org
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