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Setting the Body Clock in the Dark

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Oct. 11, 2000 -- Are you a morning lark or a night owl? If you're feeling wide awake when everyone else is sleeping, new research on sleep disorders in blind people, reported in the Oct. 12 issue of TheNew England Journal of Medicine, may help you get back in sync.

"This is an important study, which confirms and extends previous research by both U.S. and European authors," Derk-Jan Dijk, PhD, tells WebMD. "It illustrates the importance of the biological clock in sleep-wake regulation, and shows that 'treating' the clock can 'treat' some sleep disorders." Dijk, who is a chronobiologist at the University of Surrey in Guildford, England, was not involved in the study.

Normally, our body clock is set for a cycle slightly longer than 24 hours, which is why we tend to sleep later each morning, then go to bed later each night if we have time off and don't set the alarm. But the 24-hour cycle of daylight and darkness tends to get us back on track.

"People must be able to perceive light through their eyes in order to synchronize their body clocks to the 24-hour day," researcher Alfred J. Lewy, MD, PhD, tells WebMD. "Blind people drift later each day. When their clocks are reversed, telling them to sleep during the day and stay up at night, they have insomnia and daytime sleepiness," says Lewy, director of the Sleep and Mood Disorders Laboratory at Oregon Health Sciences University in Portland.

"Blind people are under constant jet lag," Sato Honma, MD, PhD, tells WebMD. He's an associate professor of medicine at Hokkaido University in Sapporo, Japan, and was not involved in the study.

In Lewy's study, seven totally blind subjects with sleep disturbances were given either melatonin or a sugar pill one hour before their preferred bedtime for several weeks. After their sleep patterns were recorded, each patient was switched over to the other treatment. Neither the patients nor the nurses knew which medication was being given.

Before treatment and while taking the sugar pill, all seven subjects had sleep problems related to an abnormal daily cycle. Most of them had a cycle longer than 24 hours, and on average, they were about half an hour off. While taking melatonin, six subjects slept better, and their wake-sleep cycle normalized to 24 hours. Three of them continued taking melatonin for three months and continued to sleep well even though the dose was gradually reduced.

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You say you are able to function well with fewer than seven hours of sleep. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get too little sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia or other conditions affecting your sleep.

Sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get too little sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have difficulty sleeping, have insomnia, or have other sleep disorders.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

It's good that you usually do get more sleep, since sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. And if you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

You say you are able to function well with fewer than seven hours of sleep. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

It's good that you usually do get more sleep because sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. And if you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get less sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have difficulty sleeping or have insomnia or other sleep disorders.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health. Whether your sleep routine involves taking a warm bath, reading a book, or meditating, it's important to keep your bedtime and routine consistent every night and wake up around the same time every morning.

Click here to read more about the importance of sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and wake time — often is the key to getting the quality sleep night after night that your body needs for optimal health. Since you usually sleep this amount, if you often aren't feeling your best, you should consider talking to your doctor. Could you have an underlying condition? Are you feeling anxious or depressed? Have you taken medication that disrupted your sleep? Do you or could you have sleep apnea? Or do you naturally require a little bit more sleep?

Although sleep is crucial for optimal health, some research suggests that sleeping too much can also have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and wake time — often is the key to getting the quality sleep night after night that your body needs for optimal health. Since you usually sleep longer, if you often aren't feeling your best, you should consider talking to your doctor. Could you have an underlying condition? Are you feeling anxious or depressed? Have you taken medication that disrupted your sleep? Do you or could you have sleep apnea? Or do you naturally require a little bit more sleep?

Although sleep is crucial for optimal health, some research suggests that sleeping too much can also have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health. Whether your sleep routine involves taking a warm bath, reading a book, or meditating, it's also important to keep bedtime consistent and wake up around the same time every morning.

Although sleep is crucial for optimal health, some research suggests that sleeping too much can have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and waking up at the same time — often is the key to getting the quality sleep night after night that your body needs for optimal health.

Since you usually get less sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia, another sleep disorder, or conditions affecting your sleep.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health.

Since you usually get less sleep, talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia or another sleep disorder or conditions affecting your sleep.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

SOURCES:

Centers for Disease Control and Prevention (CDC). Effect of short sleep duration on daily activities--United States, 2005-2008. MMWR Morb Mortal Wkly Rep 2011; 60:239.

Carskadon, MA, Dement, WC. Normal Human Sleep: An Overview. In: Principles and Practices of Sleep Medicine, Fifth, Kryger, MH, Roth, et al. (Eds), Elsevier Saunders, St. Louis, MO 2011. p.16.

Harvard University: "Sleep, Performance, and Public Safety."

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