sleep, sleeping

Why We Sleep Is Still a Mystery

January 14, 2011 07:00 AM
by Colleen Brondou
Sleep researchers don’t know why we sleep away one-third of our lives, but they are getting closer to solving the mystery.

Examining Theories to Explain Sleep

What David Braun calls “one of the greatest unsolved mysterious of science” in National Geographic’s blog NatGeo News Watch is sleep. We’re generally advised to get eight hours of it a night, but why?

Recent research by Jerome Siegel, a professor of psychiatry at UCLA and director of the Center for Sleep Research at the Semel Institute for Neuroscience and Human Behavior at UCLA and the Sepulveda Veterans Affairs Medical Center, suggests that “sleep’s primary function is to increase animals’ efficiency and minimize their risk by regulating the duration and timing of their behavior,” a UCLA statement said, according to Braun.

In the past, sleep has been considered a risk for survival because sleeping animals are more vulnerable to predators, Siegel explained. As a result, it was thought that sleep might serve an “as-yet unidentified physiological or neural function.”

But Siegel’s team came to a different conclusion after observing the sleeping patterns of a wide variety of animals—“from the platypus and the walrus to the echidna.” The team found that sleep is “highly adaptive,” similar to inactive states such as hibernation and torpor.

“We see sleep as lying on a continuum that ranges from these dormant states like torpor and hibernation, on to periods of continuous activity without any sleep, such as during migration, where birds can fly for days on end without stopping,” Siegel said.

Background: Previous studies on sleep

In the past, sleep experts believed that sleep was necessary for the rejuvenation of the brain, though the exact benefits weren’t clear. Some thought that during sleep, the brain reviews and combines the various streams of information it collected during the day. Another theory suggests that sleep allows the brain to refuel and clear out waste.

Analysis: Health benefits of sleep

While researchers continue to debate why we sleep, everyone seems to agree that getting enough sleep is important. Recent studies have discovered a relationship between lack of sleep and susceptibility to colds, highlighting the delicacy of the immune system.

In 2008, research from a Japanese university suggested that a lack of melatonin may disrupt release of estrogen, thus increasing the risk of breast cancer. In a study of 24,000 women ages 40 to 79 at Japan’s Tohoku University Graduate School of Medicine, women who slept six hours or less a night on a regular basis were 62 percent more likely to develop breast cancer than those who slept seven hours.

Related Topics: A boy who could never sleep; How much sleep do we need?

A rare brain condition called Chiari malformation kept Rhett Lamb, a 3-year-old boy, awake nearly 24 hours a day. Chiari malformation causes the lower part of the brain, the cerebellum, to extend out the bottom of the skull, pressuring the brain and spinal cord. Surgery to relieve the pressure is the most common treatment.

The National Sleep Foundation, a nonprofit organization that provides education on the importance of sleep and advocates treatment and support for sleep problems and sleep disorders, asks “How Much Sleep Do We Really Need?” The answer is more complicated than you may think.

Reference: Sleep

Use the findingDulcinea Web Guide to Sleep to learn about sleep disorders, find a sleep clinic and sleeping aids, and take a look at dreams and the latest dream research.

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