A daily dose of aspirin has
become a common treatment for people at high risk for heart attacks or strokes,
because it thins the blood and prevents clots from forming.
But does it matter when
during the day you take the drug?
A new Dutch study suggests
that people who take aspirin at bedtime might get more protection against heart
attacks or strokes.
The research involved
nearly 300 heart attack survivors who were taking aspirin to ward off a second
heart attack. During two separate three-month periods, half the patients took
100 milligrams of aspirin after they woke up in the morning while the other
half took the same dose at bedtime.
The researchers wanted to
see if taking aspirin at night could better thin a person's blood and
potentially lower their heart attack risk, said study author Dr Tobias Bonten,
who serves in the department of clinical epidemiology at Leiden University
Medical Centre in the Netherlands.
"Since the 1980s it's
been known that cardiovascular events happen more often in the morning,"
Bonten said. Morning hours are a peak period of activity for platelets, blood
cells that aid in clotting, he said. Doctors suspect that might have a hand in
the increased risk of heart attacks and strokes in the morning.
Aspirin reduces platelet activity
Aspirin reduces the
activity of platelets, and thus reduces the chance that those platelets will
clot in the bloodstream and cause a heart attack or stroke, according to the
findings. The study is scheduled for presentation at the American Heart
Association's annual meeting in Dallas.
Research presented at
meetings should be viewed as preliminary until published in a peer-reviewed
The timing of taking
aspirin, however, has not drawn much scholarly attention, said Dr Gregg
Fonarow, a spokesman for the American Heart Association.
"There really have not
been studies looking at the timing of aspirin," said Fonarow, a professor
of cardiology at the University of California, Los Angeles. "You would
imagine that timing of the dose, morning or evening, wouldn't matter very
That's because aspirin has
a long-lasting effect on platelets, helping thin the blood for days after it is
taken, he said.
"That's why, prior to
surgery, patients are told to hold off on aspirin for five to seven days, and
why it continues to thin your blood even when you miss a dose," Fonarow
But the Dutch researchers
found that taking aspirin at bedtime reduced platelet activity more than taking
it in the morning, apparently because it headed off the body's normal morning
surge in platelet activity.
The team also found that
people who took aspirin at bedtime did not suffer any more stomach upset or
other side effects than people who took it in the morning, Bonten said.
The researchers also had
hoped that taking aspirin at bedtime would lower a person's blood pressure, something
that had been observed in an earlier Spanish study. They found no difference,
however, between the blood pressures of waking and bedtime aspirin users.
You don't necessarily have
to start taking your aspirin at night right away, however. Fonarow said the
study involved too few people and did not attempt to determine whether taking a
bedtime dose will provide better protection against heart attacks or strokes.
"The key question is
whether this is enough of a difference that it would translate to improved
clinical outcomes," he said.
Until larger follow-up
studies take place, Fonarow said, people prescribed aspirin for heart problems
should continue to take it whenever in the day they like.
Another study presented at
the American Heart Association meeting found that sedentary seniors can use
exercise to slow the progression of heart disease.
Researchers looked at a
protein called Troponin T to track the rate of heart injuries in more than 300
people aged 70 and over.
Doctors found that people
who had been assigned to a year of supervised physical activity had three times
less increase in their Troponin T levels than people who had not regularly
"Our findings suggest
biochemical evidence to support the old adage, 'You're never too old to start a
physical-activity program to improve cardiac health,'" study author Dr
Christopher DeFilippi, an associate professor of medicine at the University of
Maryland School of Medicine, said in a statement.
For more information on
aspirin and heart disease, visit the American Heart Association.