Sleep Disorders

What Is Restless Legs Syndrome?

What Is Insomnia?

Sleep apnea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. Breathing pauses can last from a few seconds to minutes. They often occur 5 to 30 times or more an hour. Typically, normal breathing then starts again, sometimes with a loud snort or choking sound. Sleep apnea usually is a chronic condition that disrupts your sleep 3 or more nights each week. You often move out of deep sleep and into light sleep when your breathing pauses or becomes shallow. 

This results in poor sleep quality that makes you tired during the day. Sleep apnea is one of the leading causes of excessive daytime sleepiness.

What Is Narcolepsy?

What Is Sleep Apnea?

Insomnia is a common condition in which you have trouble falling or staying asleep. This condition can range from mild to severe, depending on how often it occurs, and for how long. Insomnia can be chronic or acute. Chronic insomnia means having symptoms at least 3 nights a week for more than a month. Acute insomnia lasts for less time. Some people who have insomnia may have trouble falling asleep. Other people may fall asleep easily but wake up too soon. Others may have trouble with both falling asleep and staying asleep. As a result, insomnia may cause you to get too little sleep or have poor-quality sleep. You may not feel refreshed when you wake up.


There are two types of insomnia. The most common type is called secondary or comorbid insomnia. This type of insomnia is a symptom or side effect of some other problem. More than 8 out of 10people who have insomnia are believed to have secondary insomnia. Certain medical conditions, medicines, sleep disorders, and substances can cause secondary insomnia. In contrast, primary insomnia is not due to a medical problem, medicines, or other substances. It is its own disorder. A number of life changes can trigger primary insomnia, including long-lasting stress and emotional upset. Insomnia can cause excessive daytime sleepiness and a lack of energy. It also can make you feel anxious, depressed, or irritable. You may have trouble focusing on tasks, paying attention, learning, and remembering. This can prevent you from doing your best at work or school. Insomnia also can cause other serious problems. For example, you may feel drowsy while driving, which could lead to an accident.

Sleep apnea often goes undiagnosed. Doctors usually cannot detect the condition during routine office visits. Also, there are no blood tests for the condition. Most people who have sleep apnea do not know they have it because it only occurs during sleep. A family member and/or bed partner may first notice the signs of sleep apnea. The most common type of sleep apnea is obstructive sleep apnea. This most often means that the airway has collapsed or is blocked during sleep. The blockage may cause shallow breathing or breathing pauses. When you try to breathe, any air that squeezes past the blockage can cause loud snoring. Obstructive sleep apnea happens more often in people who are overweight, but it can affect anyone.


Central sleep apnea is a less common type of sleep apnea. It happens when the area of your brain that controls your breathing does not send the correct signals to your breathing muscles. You make no effort to breathe for brief periods. Central sleep apnea often occurs with obstructive sleep apnea, but it can occur alone. Snoring does not typically happen with central sleep apnea.

Restless legs syndrome (RLS) is a disorder that causes a strong urge to move your legs. This urge to move often occurs with strange and unpleasant feelings in your legs. Moving your legs relieves the urge and the unpleasant feelings.  People who have RLS describe the unpleasant feelings as creeping, crawling, pulling, itching, tingling, burning, aching, or electric shocks. Sometimes, the feelings also occur in the arms. The urge to move and unpleasant feelings occur when you are resting and inactive. They tend to be worse in the evening and at night and are temporarily relieved in the morning. RLS can make it hard to fall asleep and stay asleep. It may make you feel tired and sleepy during the day. This can make it hard to learn, work, and do your normal routine. Not getting enough sleep also can cause depression, mood swings, or other health problems.

Some diseases, conditions, and medicines also may trigger RLS. For example, it has been associated with kidney failure, Parkinson disease, diabetes, rheumatoid arthritis, pregnancy, and iron deficiency. When a disease, condition, or medicine causes RLS, the symptoms usually start suddenly. Medical conditions or medicines often cause or worsen the type of RLS that starts later in life.

RLS symptoms often get worse over time. However, some people’s symptoms go away for weeks to months. If a condition or medicine triggers RLS, it may go away if the trigger is relieved or stopped. For example, RLS that occurs due to pregnancy tends to go away after giving birth. Kidney transplants (but not dialysis) relieve RLS linked to kidney failure. Treatments for RLS include lifestyle changes and medicines. Some simple lifestyle changes often help relieve mild cases of RLS. Medicines usually can relieve or prevent the symptoms of more severe RLS. Research is ongoing to better understand the causes of RLS and to find better treatments.

Narcolepsy is a disorder that causes periods of extreme daytime sleepiness. It also may cause muscle weakness. Rarely, people who have this disorder fall asleep suddenly, even if they are in the middle of talking, eating, or another activity. Most people who have narcolepsy also have trouble sleeping at night.

Narcolepsy also may cause:


  • Cataplexy - a condition that causes a sudden loss of muscle tone while you are awake. Muscle weakness can occur in certain parts of your body or in your whole body. For example, if cataplexy affects your hand, you may drop what you are holding. Strong emotions often trigger this weakness. It may last seconds or minutes.
  • Sleep paralysis - a condition that prevents you from moving or speaking while waking up and sometimes while falling asleep. Sleep paralysis usually goes away within a few minutes.
  • Hallucinations -  vivid dreams that occur while falling asleep or waking up.


Hypocretin, a chemical in the brain, helps control levels of wakefulness. Most people who have narcolepsy have low levels of this chemical. What causes these low levels is not well understood. Researchers think that certain factors may work together to cause a lack of hypocretin. Examples include heredity; brain injuries; contact with toxins, such as pesticides; and autoimmune disorders.
Narcolepsy affects between 50,000 and 2.4 million people in the United States. Symptoms usually begin during the teen or young adult years. Due to extreme tiredness, people who have narcolepsy may find it hard to function at school, work, home, and in social situations.

Narcolepsy has no cure, but medicines, lifestyle changes, and other therapies can improve symptoms. Research on the causes of narcolepsy and new ways to treat it is ongoing.