Sleep Disorders

What Are Sleep Disorders?

Sleep can be divided into two types: (REM) sleep and non-REM (NREM) sleep. NREM sleep has four stages of increasingly deep sleep. Stage 1 sleep is the lightest, while stage 4 is the deepest.

During normal sleep, you cycle through these types and stages of sleep. But if your sleep is repeatedly interrupted and you cannot cycle normally through REM and NREM sleep, you may feel tired, fatigued, and have trouble concentrating and paying attention while awake. Sleepy individuals are at greater risk for driving and other accidents.
If you have trouble getting to sleep or sleeping through the night, if you wake up too early or have a hard time waking up at all, or if you are overly tired during the day, you may have one of the following sleep problems.

Circadian Rhythm Disorders

Typically, people sleep at night -- thanks not only to the conventions of the 9-to-5 workday, but also to the close interaction between our natural sleep and alertness rhythms, which are driven by an internal "clock."

This clock is a small part of the brain called the suprachiasmatic nucleus of the hypothalamus. It sits just above the nerves leaving the back of our eyes. Light and exercise "reset" the clock and can move it forward or backward. Abnormalities related to this clock are called circadian rhythm disorders ("circa" means "about," and "dies" means "day").

Circadian rhythm disorders include jet lag, adjustments to shift work, delayed sleep phase syndrome (you fall asleep and wake up too late), and advanced sleep phase syndrome (you fall asleep and wake up too early).

Insomnia

People who have insomnia don't feel as if they get enough sleep at night. They may have trouble falling asleep or may wake up frequently during the night or early in the morning. Insomnia is a problem if it affects your daytime activities. Insomnia has many possible causes, including stress, anxiety, depression, poor sleep habits, circadian rhythm disorders (such as jet lag), and taking certain medications.

Snoring

Many adults snore. The noise is produced when the air you inhale rattles over the relaxed tissues of the throat. Snoring can be a problem simply because of the noise it causes. It may also be a marker of a more serious sleep problem called sleep apnea.

Sleep Apnea

Sleep apnea occurs when the upper airway becomes completely or partially blocked, interrupting regular breathing for short periods of time - which then wakes you up. It can cause severe daytime sleepiness. Evidence is building that, left untreated, severe sleep apnea may be associated with high blood pressure and the risk of stroke and heart attack.

Pregnancy and Sleep

Women often experience sleepless nights and daytime fatigue in the first and third trimesters of their pregnancy. During the first trimester, frequent trips to the bathroom and morning sickness may disrupt sleep. Later in pregnancy, vivid dreams and physical discomfort may prevent deep sleep. After delivery, the new baby's care or the mother's postpartum depression may interrupt sleep.What Are Sleep Disorders? continued...

Narcolepsy

Narcolepsy is a brain disorder that causes excessive daytime sleepiness. There is a definite genetic component, but most patients have no family history of the problem. Though dramatic and uncontrolled "sleep attacks" have been the best-known feature of narcolepsy, in reality many patients do not have sleep attacks. Instead, they experience constant sleepiness during the day.
Restless Legs Syndrome

In people who have restless legs syndrome, discomfort in the legs and feet peaks during the evening and night. They feel an urge to move their legs and feet to get temporary relief, often with excessive, rhythmic, or cyclic leg movements during sleep. This can delay sleep onset and cause brief awakening during sleep. Restless legs syndrome is a common problem among middle-aged and older adults.

Nightmares

Nightmares are frightening dreams that arise during REM sleep. They can be caused by stress, anxiety, and some drugs. Often, there is no clear cause.

Night Terrors and Sleepwalking

Both night terrors and sleepwalking arise during NREM sleep and occur most often in children between the ages of 3 and 5. A night terror can be dramatic: Your child may wake up screaming, but unable to explain the fear. Sometimes children who have night terrors remember a frightening image, but often they remember nothing. Night terrors are often more frightening for parents than for their child. Sleepwalkers can perform a range of activities -- some potentially dangerous, like leaving the house - while they continue to sleep.
What Causes Sleep Disorders?

Insomnia

Insomnia may be temporary and stem from a simple cause, such as jet lag. Short-term insomnia may also be caused by an illness, a stressful event, or drinking too much coffee. Many medications have insomnia as a side effect.

Long-term insomnia may be caused by stress, depression, or anxiety. People can also become conditioned to insomnia: They associate bedtime with difficulty, expect to have trouble sleeping (and thus do), and become irritable (which can cause more insomnia). This cycle can be maintained for several years.

Circadian rhythm disorders are an important but less common cause of insomnia. People who abuse alcohol or drugs often suffer from insomnia.

Snoring and Sleep Apnea

When you fall asleep, many muscles in your body relax. If the muscles in your throat relax too much, your breathing may be blocked and you may snore. Sometimes, snoring is caused by allergies, asthma, or nasal deformities that make breathing difficult.

Apnea means "no airflow." Obstructive sleep apnea was thought to be a disorder primarily of overweight, older men. But abnormal breathing during sleep can affect people of any age and either sex, and at least 30% of those affected are not obese. Researchers now know that in many cases of sleep apnea, the obstruction in the airways is only partial. Most people with sleep apnea have a smaller-than-normal inner throat and other subtle bone and soft-tissue differences.