People with high blood pressure who get less than the standard
amount of sleep may face an increased risk of heart disease
and stroke, researchers reported.
In a study of more than 1,200 Japanese adults with high
blood pressure, the investigators found that those who slept
for less than 7.5 hours each night were more likely to suffer
a heart attack or stroke or die of cardiac arrest over a
At particular risk were "short sleepers" who failed to
have a blood-pressure dip that normally occurs overnight.
The findings suggest that doctors caring for patients with
high blood pressure should ask them about their sleep habits,
the researchers report in the Archives of Internal Medicine.
A relatively small number of people are both short sleepers
and have no overnight decline in blood pressure, note the
researchers, led by Dr. Kazuo Eguchi of Jichi Medical University
in Japan. Therefore, "it is a group that could be easily
identified and monitored more closely."
The findings are based on data from 1,255 men and women
with high blood pressure who were between 33 and 97 years
old; the average age was 70. The researchers used portable
blood pressure monitors to record each participant's blood-pressure
changes over a 24-hour period, and then followed the patients
over an average of 50 months.
During that time, there were 99 heart attacks, strokes
or deaths from cardiac arrest.
In general, Eguchi's team found, men and women who slept
for less than 7.5 hours per night had a 68-percent higher
risk of one of these cardiovascular complications than their
Similarly, the risk was greater among participants who
had shown no drop in their overnight blood pressure, versus
those who had.
But the combination of short sleep and non-dipping blood
pressure conferred the highest risk -- a more than four-fold
greater chance of heart attack, stroke or cardiac death.
Chronic sleep deprivation has been linked to a higher risk
of a number of health problems, including diabetes, coronary
heart disease and obesity.
The researchers suspect that a lack of sleep leads to increased
nervous system activity throughout the day, which may in
turn stress the cardiovascular system. Non-dipping overnight
blood pressure has also been tied to increased nervous system
activity during the day, Eguchi's team notes.
Therefore, they suggest, the combination might have an
"interactive effect to increase cardiovascular risk."
SOURCE: Archives of Internal Medicine, November 10, 2008.