Everyone has suffered from a lack of sleep at one time or another. But some people have medical disorders that cause poor sleep on a regular basis. There are many types of sleep disorders and, in many cases, a combination of factors may cause sleep problems.
Primary Sleep Disorders
Insomnia is the inability to fall asleep or stay asleep.
Short-term (situational) insomnia may be related to stressful situations such as illness, work/school demands or emotionally upsetting events in a person’s life. Situational insomnia is the most common reason for poor sleep.
Chronic insomnia — at least three months of poor sleep most nights — may be related to another unrecognized sleep disorder such as sleep apnea or restless legs syndrome. In many cases, more than one factor may cause insomnia.
Sleep Apnea is a temporary suspension of breathing (10 or more seconds) that occurs repeatedly during sleep. Sleep apnea causes a person to wake up or to come out of a deep level of sleep into a more shallow level of sleep.
Symptoms include loud snoring, gasping, restless sleep, and daytime sleepiness/fatigue, headaches, blurred vision, dizziness, fatigue, leg swelling, droopy eyelids, shortness of breath, irritability, and memory problems. Excessive weight may play a role. Sleep apnea is twice as common in men as in women, and women often have different symptoms from men.
There are two main types of sleep apnea:
- Obstructive sleep apnea, in which the airway becomes obstructed and prevents the flow of air
- Central sleep apnea, in which the brain does not send the signal to the muscles to take a breath
A person also may have mixed sleep apnea (both obstructive sleep apnea and central sleep apnea).
The breathing obstruction in obstructive sleep apnea occurs in the throat (pharynx) and other soft tissues of the upper airway. Obstructive sleep apnea results from collapse and obstruction of the airway. This is caused by a structurally small upper airway and a loss of muscle tone. The level of airway closure varies with changes in body and head position, sleep state, and muscular tone (the relationship between the muscles and the nerves).
Although a diagnosis of sleep apnea often will be suspected on the basis of a person’s history, tests can be done to confirm the diagnosis. In addition, a physical exam may reveal a long and wide soft palate, a large swollen uvula, large tonsils and excess tissue in airway walls. In the lower throat, the tongue and tonsils may be larger than normal.
Narcolepsy is unexplained sleepiness at inappropriate times despite adequate nighttime sleep. Narcolepsy is a syndrome that involves vivid dreams, sleep paralysis and cataplexy (a condition in which a person suddenly feels weak and collapses at moments of strong emotion). Symptoms may occur all at once or gradually over many years.
Restless Legs Syndrome
Restless Legs Syndrome is a chronic neurological disorder characterized by unpleasant sensations in the legs and an irrepressible urge to move the legs when resting to relieve these feelings. Symptoms worsen in the evening and at rest, preventing sleep. Symptoms are relieved by moving the legs. Suffers describe the sensation as energy, creepy-crawly, electric shock, or pain. One-third of people with this disorder have had symptoms since childhood. The symptoms tend to become more severe with aging.
Periodic Limb Movement Disorder (PLMD)
Periodic Limb Movement Disorder (PLMD) is a disorder characterized by periodic, involuntary leg twitching or jerking movements that occur during sleep. More than 80 percent of people with restless legs syndrome also experience PLMD. The movements caused by PLMD are involuntary, unlike RLS. Although most people with RLS develop PLMD, most people with PLMD do not experience RLS.
Inadequate Sleep Hygiene
Inadequate Sleep Hygiene —bad sleep habits — is a sleep disorder caused by the performance of daily living activities that are inconsistent with the maintenance of good quality sleep and full daytime alertness. This may involve lifestyle practices that keep a person awake and/or practices that bring disorder to a person’s sleep schedule.
Jet Lag is a temporary disorder that causes fatigue, insomnia and other symptoms as a result of air travel across time zones.
People who work second or third shifts may have difficulty sleeping during the day and trouble staying awake during their shift at night. Workers who are most affected work between 11:00 pm and 7:00 am and those who do rotating shifts. Night shift workers are likely working during the time in their circadian rhythm (the body’s internal regulator of sleep and wake) when their brain is most sleepy.
Sleepwalking is a disorder characterized by walking or other activity while seemingly still asleep. Sleep walking may occur at any age, but most often occurs in children ages 6 to 12.
Night Terror (Sleep Terror)
Night Terror or Sleep Terror is a common sleep disorder among children involving abrupt awakening from sleep in a terrified state. A child may scream and shake, and the child is difficult to wake. Night terrors may be associated with emotional tension, stress or conflict. Night terror is similar to nightmares except that nightmares usually occur during REM sleep. The disorder usually ends around the time a child reaches grade school age.
Secondary Sleep DisordersIn addition to primary sleep disorders, more than 50 secondary sleep disorders have been identified, including snoring, eating disorders, bedwetting, circadian rhythm sleep disorder, hypersomnia, environmental sleep disorder, teeth grinding, delayed sleep phase and many other conditions.
Last Review Date: Apr. 9, 2010
Online Editor(s): Richard Petre