MONDAY, Aug. 29 (HealthDay News) -- If you sleep poorly, your
chances of developing high blood pressure may increase, new
In the study, men with the lowest level of the deeper stages of
slumber, known as slow-wave sleep, had an 80 percent higher chance
of developing high blood pressure than men with the highest level
of this restorative sleep.
The link held regardless of other factors, such as obesity or
how long the men slept.
"Reductions in the deepest stage of sleep is specifically associated with an increased risk of developing high blood pressure," said Dr. Susan Redline, the Peter C. Farrell Professor of Sleep Medicine at Brigham & Women's Hospital, Beth Israel Deaconess Medical Center and Harvard Medical School.
The study, published in the Aug. 29 online edition of the
Hypertension, reinforces other research that has linked sleep problems with a raised risk of obesity and cardiovascular problems, among other ills.
Redline evaluated 784 men, average age 75, who were part of the
Outcomes of Sleep Disorders in Older Men Study. In 2003-05, the men
did not have high blood pressure. Ideally, blood pressure readings
should be below 120/80. When they returned for a follow up in
2007-09, the investigators found that 243 men had developed high
The researchers divided the men into four groups, from those
with the lowest amount of slow-wave sleep to the highest.
After the researchers took into account age, race, body mass
index and other factors, the link between low slow-wave sleep and
higher blood pressure held. Even when the researchers took into
account sleep-disordered breathing and the length of overall sleep,
the link held.
Slow-wave sleep decreases with age, Redline said. "Kids may have
40 percent slow-wave sleep [of total sleep]," she said, but healthy
adults, overall, may have only about 25 percent.
In this study, the men averaged 11.2 percent of slow-wave sleep,
she said. Those in the lowest of the four groups averaged only 4
percent or less. Other studies have shown that slow-wave sleep is
lower in older men than in women.
While the study found an association between slow-wave sleep and
high blood pressure, it did not prove a cause-and-effect.
The new research adds to information about the importance of
sleep, said Dr. Alberto Ramos, co-director of the University of
Miami Sleep Disorders Center.
Experts agree, he said, that not enough sleep, over time, can
boost the risk of high blood pressure.
The new study, he noted, goes further by suggesting that "the
quality of your sleep, specifically the amount of deep sleep, is as
important in your overall health -- or at least in developing high
blood pressure -- as the actual amount of time you sleep."
Exactly why this is so is not known for sure, according to
Redline and Ramos.
"When you go to sleep, blood pressure normally falls," Redline said. "A lot of that fall occurs during slow-wave sleep." When that typical drop in night-time pressure is affected by a lack of deep sleep, "it may set you up for daytime elevations," she added.
Ramos agreed that might explain the link.
Adults can take measures to try to increase slow-wave sleep,
Redline said. "Anything that wakes you up repeatedly will disrupt
your slow-wave sleep," she noted.
Getting treated for underlying disorders that can wake you up --
such as sleep apnea -- could help, she said.
The take-home message, Ramos said, is to pay attention to sleep
quality, not just the length of your sleeping hours. Even though
the link between low deep sleep and high blood pressure held after
taking weight into account, Ramos noticed those in the lowest
deep-sleep groups also tended to be heavier than the others.
Avoiding obesity would be a good idea, he said.
To learn more about sleep, visit the
American Academy of Sleep Medicine.