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Understanding Sleep Problems -- The Basics


What Causes Sleep Disorders? continued...

Drops in blood oxygen during sleep -- once thought to be the cause of waking up due to obstructive sleep apnea -- may or may not be present. Most likely, awakening occurs with the body's increased effort required to overcome the obstruction of the airway.

Drinking alcohol can make obstructive sleep apnea worse because it relaxes muscles that maintain an open airway.

A rare form of sleep apnea called central sleep apnea occurs when signals from the brain to your muscles decrease or stop for a short time. You may not snore if you have central sleep apnea.

Pregnancy and Sleep

Fatigue during the first trimester of pregnancy is likely caused by changing levels of hormones, such as progesterone. Toward the end of pregnancy, some women find it difficult to sleep because of the uncomfortable size of their abdomen. Some women are too excited, anxious, or worried about becoming mothers to sleep well. Other women who are pregnant complain that vivid dreams prevent them from getting restful sleep. Sleep apnea, especially if it's severe and causes your blood oxygen level to drop during sleep, is a risk to the fetus.


The cause of narcolepsy is not clear. Genetic and environmental factors likely play a role, although the data on genetic factors is still speculative and not well studied. There are some rare nerve disorders that may be linked to narcolepsy.

Restless Legs Syndrome

There are many possible causes of restless legs syndrome, including kidney failure, nerve disorders, vitamin and iron deficiencies, pregnancy, and some medications (such as antidepressants). Recent studies have shown a strong genetic link and researchers have been able to isolate a gene that may be responsible for at least half of all cases of the disorder.

Nightmares and Night Terrors

Nightmares can be triggered by a frightening or stressful event, a fever or illness, or use of some medications or alcohol. Night terrors are most common in pre-school children, but they also can affect adults who are experiencing emotional or psychological problems.

Other Factors in Sleep

  • Young age. Infants may sleep up to 16 hours a day. But most won't sleep through the night without a feeding until 4 months of age. School-aged children may sleep 10 hours a day. Their sleep may be disturbed by an illness or fever. Call your doctor if your child has a fever and is sluggish when waking up.
  • Old age. People over age 60 may not sleep as deeply as younger people. Sleep apnea is also more common among older people.
  • Lifestyle. People who drink coffee, smoke cigarettes, or drink alcohol are more likely to have sleep problems than people who do not.
  • Medication. Many drugs can cause sleeplessness. Others can cause daytime fatigue.
  • Depression and anxiety. Insomnia is a common symptom of depression and anxiety.
  • Heart failure and lung problems. Some people find it difficult to sleep at night because they become breathless when they lie down. This can be a symptom of heart failure or a problem with the lungs.


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WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on April 29, 2014
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