To Not Sleep, Perchance to Shorten Your Life

WEDNESDAY Sept. 1, 2010 -- Shortchanging yourself on sleep could shave years off a man's life.

So claims a new study that found men who reported having insomnia or who slept for short periods of time were much more likely to die over a 14-year period.

"Insomnia has potentially very severe side effects," said study co-author and sleep researcher Edward Bixler. "It needs to be treated, and more effort needs to be put into sorting out better treatments."

Female insomniacs could be suffering the same fate, but the researchers only followed them for 10 years and researchers didn't notice any significant difference in mortality rates.

Previous research has looked at sleep's effects on life span, but the new study is unique because it takes into account both people's perceptions about how much sleep they're getting (which can be wrong) and the actual amount of sleep they got in a laboratory.

Bixler and his colleagues recruited more than 1,700 people from central Pennsylvania and followed the men (average age 50) for 14 years and the women (average age 47) for a decade. The participants answered questions and spent a night in a sleep laboratory.

The researchers report their findings in the Sept. 1 issue of the journal Sleep.

About a fifth of the men died during the study period, while 5 percent of the women did. The difference may be because women live longer than men and the study followed women for a shorter period, said Bixler, a professor of psychiatry at the Pennsylvania State University College of Medicine.

Even after adjusting their statistics so they wouldn't be thrown off by factors such as the prevalence of sleep apnea, the researchers found that self-described male insomniacs who slept fewer than six hours in the sleep lab were several times more likely to die during the 14-year period compared to "good sleepers."

Among men, about 9 percent of "good sleepers" died during the study period, compared to more than half -- 51 percent -- of insomniacs with short sleep duration.

Of all the people in the study, 8 percent of women and 4 percent of men both reported insomnia and had trouble getting much sleep in the lab.

Why might sleep problems shorten lives? Some evidence suggests they may contribute to clogged arteries or disrupt the immune system, said Dr. B. Tucker Woodson, chief of the division of sleep medicine at the Medical College of Wisconsin.

The study doesn't definitively prove that poor sleep will directly cause a man to die earlier; there could be other factors at play.

As for women, they aren't in the clear, Bixler said. Since they live longer, it may take a study of a longer duration to figure out whether they suffer from a similar effect, he noted.

And there's another complicating factor, said J. Todd Arnedt, director of the Behavioral Sleep Medicine Program at the University of Michigan. While he said the study was "well-conducted," the men appear to have been sicker than the women, potentially throwing off the results.

More information

The U.S. National Library of Medicine has details on sleep disorders.

Posted: September 2010


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