CHICAGO (Reuters) - Older people who
have significant trouble staying awake
during the day have more than four times
the normal risk of having a stroke, U.S.
researchers said on Thursday.
They also found a higher risk of heart
attacks and other cardiovascular
problems in seniors who regularly nod
off during the day without planning to.
"Even when we controlled for things like
hypertension, diabetes, physical
activity, obesity and socioeconomic
status, we found that people who had
significant daytime dozing were much
more likely to end up with stroke," said
Bernadette Boden-Albala of
Columbia University in
Dozing During Daytime a warning sign of
Her study of 2,153 adults with an
average age of 73 found the risk of
stroke was 2.6 times greater for those
classified as doing "some dozing" during
the day compared to those with "no
dozing." Those in the "significant
dozing" group had a 4.5 times greater
The study, presented at an
American Stroke Association conference
New Orleans, is one of the first
to look at the relationship between
unplanned napping and "vascular events"
such as stroke.
Other studies have found that people
with sleep apnea who briefly stop
breathing throughout the night are at
high risk of stroke. This can cause
Boden-Albala's study involved mostly
Hispanic men and women over 40 living in
the same community in
New York City. None had suffered
The researchers asked people to rate
how often they dozed in specific
situations, such as watching TV, sitting
quietly after a lunch without alcohol
and stopping briefly in traffic while
driving. Some 44 percent reported no
dozing, 47 percent had some dozing and 9
percent reported significant dozing.
After 2 1/2 years, they checked to
see how many had strokes or other
vascular problems, such as a heart
attack. They detected 40 strokes and 127
other vascular events.
They found those who had the most
trouble staying awake had the highest
stroke risk, but the biggest surprise
was in the moderate dozing group.
"We found that group was also
significantly associated with about a
2.5-fold increased risk of stroke and
about a 60 percent increased risk of
having any kind of vascular event,"
Boden-Albala said in a telephone
She said it is not clear what is
causing the daytime sleepiness or if
there is a link with sleep apnea.
"Whether it is sleep deprivation or
sleep apnea, physiological changes are
occurring that may be related to this
increased risk. I think we may need to
investigate that further," she said.
A separate study at the conference
found moderate aerobic fitness helped
protect people from stroke, even if they
had other risk factors such as heart
disease or diabetes.
The study, which involved more than
60,000 people, is the first to single
out the benefits of aerobic fitness on
"We found that a low-to-moderate
amount of aerobic fitness for men and
women across the whole adult age
spectrum would be enough to
substantially reduce stroke risk," said
Steven Hooker of the
University of South Carolina.
About 780,000 U.S. adults suffer a
stroke each year, and about 150,000 of
those will die.