TUESDAY, July 5 (HealthDay News) -- Women who sit for long
periods of time on a regular basis have a two- to threefold
increased risk of developing a potentially deadly blood clot in
their lungs, a new study finds.
The researchers said their study is the first to prove that an
inactive lifestyle increases the risk of developing a pulmonary
embolism, which occurs when part or all of a blood clot that forms
in the deep veins of the legs travels through the bloodstream to
the lungs.
Sudden shortness of breath, severe chest pain and coughing that
may produce blood are among the symptoms of pulmonary embolism, in
addition to excessive sweating, fainting and weak pulse.
The new study included 69,950 female nurses who were followed
for 18 years and every two years provided details about their
lifestyle habits. Women who spent most of their time sitting (more
than 41 hours a week outside of work) were two times more likely to
develop a pulmonary embolism than those who spent the least time
sitting (less than 10 hours a week outside of work).
The link between levels of physical activity and pulmonary
embolism risk remained conclusive after accounting for such factors
as age, smoking and body mass index (a measurement based on height
and weight), the researchers said.
The investigators also found an association between physical
inactivity and high blood pressure and heart disease, which
suggests that physical inactivity could be one of the hidden
mechanisms that connect arterial disease and venous disease.
Public health campaigns that encourage people to be physically
active could reduce the incidence of pulmonary embolism, concluded
study author Dr. Christopher Kabrhel, attending physician in the
emergency medicine department at Massachusetts General Hospital,
and colleagues, in a statement.
Their study was published online July 4 in the
BMJ.
The findings reinforce "the notion that prolonged inactivity
increases the risk of venous thromboembolism [pulmonary embolism or
deep-vein thrombosis], and it shows how this occurs in everyday
life," Dr. James Douketis, director of vascular medicine at
McMaster University in Hamilton, Ontario, Canada, and colleagues
wrote in an accompanying editorial.
Although the risk is small -- equal to seven extra cases per
10,000 person-years -- the results could have major public health
ramifications, the editorialists noted.
The study offers "additional evidence to prove what we've
already seen in other contexts," Dr. Furqan Tejani, director of
advanced cardiovascular imaging the State University of New York
Downstate Medical Center in New York City, said in an e-mailed
statement.
"For instance, Olympic athletes who took trips from Europe to Australia were found to have deep venous thrombosis and pulmonary embolism. Recently, in fact, one of the Williams sisters [tennis star Serena Williams] also had pulmonary embolism," Tejani noted.
"Whether travel and prolonged sitting had anything to do with it is not clear, but because a mounting body of evidence pointing to the fact that it may be, it is recommended that one take a baby aspirin before long-haul travels described as lasting more than eight hours," Tejani added. "Certainly it is recommended to at least get up and walk around the aircraft cabin and do calf muscle exercises on a regular basis while en route."
More information
The U.S. National Heart, Lung and Blood Institute has more about
pulmonary embolism.