Too much sitting has been linked to
increased risk for health problems such as heart failure and earlier death.
Now, a new study finds older adults who sit too much are more likely to be
disabled – regardless of their exercise habits.
"Sedentary behaviour is its own
separate risk factor [for disability]," said study researcher Dorothy
Dunlop, a professor of medicine at the North-western University's Feinberg
School of Medicine. She evaluated the exercise habits of more than 2000 men and
women, aged 60 and above, and their ability to perform normal everyday
"Regardless of how much time they
spent in moderate physical activity, the more time they spent being sedentary,
the more likely they were to be disabled," Dunlop said.
However, another expert wonders if the
relationship may occur in the opposite way – that the more disabled people
are, the more sedentary they are due to inability to exercise.
The study was supported in part by the US
National Institute for Arthritis and Musculoskeletal Diseases. It was published
online in the Journal of Physical Activity & Health.
Dunlop and her colleagues evaluated
responses given to the US National Health and Nutrition Examination Survey. The
men and women answering the survey wore accelerometer devices to measure their
activity on at least four different days between 2002 and 2005.
Few met the guidelines of getting moderate
activity for 2.5 hours a week, Dunlop said. Only about 6 percent met that goal,
and the other 94% did not, the study found.
On average, the men and women spent nine
hours a day being sedentary during waking hours. About 4% reported being
disabled. Disability was defined as having much difficulty (or inability) in
performing activities of daily living, such as getting out of bed, dressing and
For each additional daily hour of being
sedentary, the odds of disability rose about 50%, Dunlop said. For instance, a
woman aged 65 who was sedentary for 13 hours a day was 50 percent more likely
to be disabled than a woman who was sedentary for 12 hours, she explained.
is it about sitting?
What is it about sitting? Dunlop can't say
for sure, but said experts think that sitting for an extended period causes
muscles to burn less fat and blood to flow more sluggishly. Idle muscles and
sluggish blood flow can contribute to high blood pressure, heart disease,
swollen ankles and diabetes.
Dunlop's study found a link, not a
The connection may actually go the other
way, said Andrea LaCroix, a professor of epidemiology in family and preventive
medicine and director of the Women's Health Centre of Excellence at the
University of California, San Diego School of Medicine. She recently found a
link in her own study between higher amounts of sedentary time and higher risk
of death in older women.
In the new study, however, the disability
may be driving the inactivity, she said. "The more disabled people are,
the more sedentary, because they are unable to exercise," LaCroix said.
Among the study's limitations, she noted,
was that it looks only at a snapshot in time – four days of tracking over a
few years. A better approach would be to follow people over time and see if
being sedentary leads to disability, said LaCroix, who is also an affiliate
investigator at the Fred Hutchinson Cancer Research Centre, in Seattle.
The take-home message, study author Dunlop
said, is that older adults, regardless of how much they exercise, should
decrease their sedentary behaviours. So, she's still encouraging exercise. But
if that's difficult, decreasing sitting time is another goal.
How to do that? Stand up when you talk on
the phone, she suggested. Park in a far-away space at the mall or market when
you shop. At work or home, walk around a bit when you get up for coffee or
water, she advised. Walk to nearby errands instead of taking the car. If you're
able, take stairs, not elevators. You can use a pedometer to track your
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