April 1, 2009 -- Insomniacs who sleep less than five hours a night are five times more likely to develop high blood pressure than sound sleepers who get enough rest, a new study shows.
The link between another sleep disorder, sleep apnea, and hypertension is well established. But the newly published study is one of the first to find that insomnia also raises the risk for high blood pressure.
"We have known for many years that insomniacs have a high risk for depression and other psychiatric disorders," study researcher Alexandros N. Vgontzas, MD, tells WebMD. "Now we are increasingly recognizing the association with medical morbidities like high blood pressure."
Vgontzas, who directs the Sleep Research and Treatment Center at the Penn State College of Medicine, says the major strength of the new study is that it included both subjective and objective measures of insomnia.
Poor Sleepers vs. Sound Sleepers
The study involved 1,741 randomly selected adults living in central Pennsylvania who agreed to spend a night in a sleep laboratory.
Based on their responses to questionnaires designed to assess sleep quality, more than half of the study participants were classified as being normal sleepers, 8% had insomnia with symptoms persisting for at least one year, and 22% were classified as being poor sleepers who had difficulty falling asleep, staying asleep, or had poor-quality sleep.
A little more than half of the participants slept more than six hours, which was considered normal.
The sleep assessment revealed that:
- People who slept less than five hours a night and had insomnia had the highest risk of hypertension, with a fivefold greater risk than people who slept more than six hours a night without insomnia or poor sleep.
- Those who slept five to six hours a night and had insomnia had a 3.5-fold increase in high blood pressure risk, compared to normal sleepers without insomnia or poor sleep.
- The high-blood-pressure risk among people who reported having insomnia, but slept for more than six hours during their night in the sleep laboratory, was similar to people who described themselves as normal sleepers.
The findings are published in the April issue of the journal Sleep.
"We found little increase in risk among people who were unhappy with the quality of their sleep but who did not have evidence of insomnia on objective measurement," Vgontzas says.
Getting a Good Night's Sleep
Sleep researcher William C. Kohler, MD, tells WebMD that he is not surprised by the findings.
He points to a growing body of research linking lack of sleep to a wide range of medical conditions, including obesity in adults and children, and related diseases like heart disease and diabetes.
Kohler is medical director of the Florida Sleep Institute in Spring Hill and a spokesman for the American Academy of Sleep Medicine.
"There is more awareness about the importance of sleep to our overall health, but despite this, very few physicians adequately screen their patients for sleep problems," he says. "This should be routine."
The typical adult needs about eight hours of sleep a night, but Kohler says a few people can get by on four or five hours and others need nine or 10.
"If your body needs eight hours and you typically sleep for five or six, you will pay for it by being tired all the time and not functioning all that well," he says.
He says insomniacs can take steps to improve their sleep, including:
- Reserve the bedroom for sleeping and sex. Your sleeping space should not do double duty as a home office or media center. "A person with sleep problems shouldn't watch TV in bed, eat in bed, or even read in bed," Kohler says. "The bedroom should be for sleeping."
- If you don't fall asleep in 20 minutes, get up and do something boring. The bed often becomes a war zone for people who have trouble sleeping, he says. Instead of lying there tossing and turning, get up and perform an activity that isn't too stimulating until you feel tired.
- Have a small snack. Kohler recommends a glass of milk, cheese, or even turkey
- Create a nice sleep environment. The lights should be off and you should be comfortable.
- Exercise, but not just before going to bed. Studies show that exercising improves sleep, but doing it too close to bedtime can keep you awake.