The Mystery of Sleep
The Mystery of Sleep: Science (Part 1 of 3)
ORLANDO, Fla. (Ivanhoe Broadcast News) -- Every living creature does it. We can't survive without it. Just what goes on during the one third of our life that we spend sleeping? And how much sleep is enough?
New research shows that last question carries more weight than you might think. Lack of sleep causes inattentiveness and makes it difficult to learn, but neuroscientist Jerome Siegel, Ph.D., of UCLA's Center for Sleep Research, has another question. "The more subtle question is: If you don't get sleep, will it shorten your life span?"
Dr. Siegel studies dogs with narcolepsy -- a serious sleep condition. He's been fascinated with the science of sleep for 30 years. He says sleep studies often uncover more questions than answers.
"Under extreme conditions in animals, if they're totally sleep-deprived for periods of weeks, they will die," Dr. Siegel tells Ivanhoe. "They will die sooner than if they don't get food."
During sleep, heart rate, blood pressure and temperature drop. The body also secretes growth hormone, which regulates muscle mass in adults. It also secretes leptin, a hormone that tells the body it's had enough food.
Problems start when you don't get enough shut-eye. A recent study shows when healthy volunteers were sleep-deprived, they became pre-diabetic after just one week.
And that's not all.
"Two nights of sleep restriction to four hours of bedtime resulted in cravings for especially sweets, candies, cookies, types of food that we generally refer as junk food," says Esra Tasali, M.D., a pulmonologist at University of Chicago.
Dr. Tasali says sleep loss creates even more problems for dieters. "The appetite hormone ghrelin goes up, which again signals the brain that you have to have more food."
Most scientists agree sleep boosts the immune system. And Dr. Siegel says it's the only time the brain gets a break. "Unlike muscles, for example, which can rest when you sit down, brain cells are pretty much working 24 hours a day," he says.
So how much sleep do you need? One study shows people who slept seven hours a night were more likely to be alive five years later than those who slept six and those who slept eight hours a night.
Dr. Siegel says, "If you tell people who are sleeping nine hours a night to cut their sleep to seven hours, is their life span going to be extended? That seems unlikely, but it's possible."
Whether you rack up seven hours or not, the important thing to remember is: As you're heading off to dreamland, your body has a full night's work ahead of it.
This article was reported by Ivanhoe.com, who offers Medical Alerts by e-mail every day of the week. To subscribe, go to: http://www.ivanhoe.com/newsalert/.
If you would like more information, please contact:
John Easton
University of Chicago Hospitals
5841 South Maryland Ave. (MC 6063)
Chicago, IL 60637
John.Easton@uchospitals.edu
posted by Bill at 5:11 PM
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