What is the body clock?
The body's "biological clock," or 24-hour cycle (circadian rhythm), can be affected by light or darkness, which can make the body think it is time to sleep or wake up. The 24-hour body clock controls functions such as:
How are body clock problems and sleep problems connected?
Body clock sleep problems have been linked to a hormone called melatonin. Light and dark affect how the body makes melatonin. Most melatonin is made at night. During the day, light tells your body to make less melatonin. If you work at night in artificial light, your body may be making less melatonin than it needs.
Some people—such as those who can't sleep until very late and those who go to bed very early—have circadian (say "ser-KAY-dee-un") rhythms that are different from those of most people. Other people with sleep problems may have regular circadian rhythms but have to adjust them to new situations, such as working a night shift.
What sleep problems are related to problems with your body clock?
Things that may affect melatonin production and can cause sleep problems include:
Other sleep problems related to the body clock include:
How can you treat sleep problems related to your body clock?
How you treat a sleep problem related to your body clock depends on what is causing the problem. Here are some tips for the most common problems.
Taking melatonin supplements may help reset your body clock. Studies show that melatonin has reduced the symptoms of jet lag for people flying both east and west.1
Suggestions about times and dosages vary among researchers who have studied melatonin. Doctors recommend that you:
The safety and effectiveness of melatonin have not been thoroughly tested. Taking large doses of it may disrupt your sleep and make you very tired during the day. If you have epilepsy or are taking blood thinners such as coumadin (Warfarin), talk to your doctor before you use melatonin.
The sleeping pills eszopiclone (Lunesta) and zolpidem (Ambien) have been studied for jet lag. They may help you sleep despite jet lag if you take them before bedtime after you arrive at your destination. Side effects include headaches, dizziness, confusion, and feeling sick to your stomach.
For more information on jet lag, see:
If you work the night shift or rotate shifts, you can help yourself get good sleep by keeping your bedroom dark and quiet and by taking good care of yourself overall. In some cases, prescription medicine or over-the-counter supplements may help. Here are some tips on sleeping well when you do this type of shift work:
For more information, see the topic Shift Work Sleep Disorder.
Some people, no matter what they do, have trouble falling asleep at night and being up early during the day. This may or may not cause problems for them. It depends on their lifestyle and work or school schedule. If you are one of those night owls, there are things you can try so that you fall asleep earlier and sleep through the night.
People who fall asleep very early and wake up before dawn may try the following to try to stay up later at night and sleep later in the morning.
After you get treatment for the illness or health problem that is causing your sleep problem, you will need to practice good sleep habits. This includes getting regular exercise (but not within 3 or 4 hours of your bedtime), going to bed at the same time each day, and using the bed only for sleep and sex.
For more tips on improving sleep habits, see:
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|Insomnia: Improving Your Sleep|
|Sleep Problems: Dealing With Jet Lag|
- Herxheimer A (2008). Jet lag, search date June 2008. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
Other Works Consulted
- Reite M, et al. (2002). Insomnia complaints. In Concise Guide to Evaluation and Management of Sleep Disorders., 3rd ed., chap. 3. Washington, DC: American Psychiatric Publishing.
|Primary Medical Reviewer||Anne C. Poinier, MD - Internal Medicine|
|Specialist Medical Reviewer||Lisa S. Weinstock, MD - Psychiatry|
|Last Revised||December 1, 2011|
Last Revised: December 1, 2011
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