Definition of Sleep walking:

Sleep walking is a disorder that occurs when a person walks or does another activity while they are still asleep.

Causes, incidence, and risk factors:

The normal sleep cycle has distinct stages, from light drowsiness to deep sleep. During rapid eye movement (REM) sleep, the eyes move quickly and vivid dreaming is most common.

Each night people go through several cycles of non-REM and REM sleep. Sleep walking (somnambulism) most often occurs during deep, non-REM sleep (stage 3 or stage 4 sleep) early in the night. If it occurs during REM sleep, it is part of REM behavior disorder and tends to happen near morning.

The cause of sleep walking in children is usually unknown but may have to do with fatigue, lack of sleep, or anxiety. Sleep walking in adults can have to do with mental disorders, reactions to drugs and alcohol, or medical conditions such as partial complex seizures. In the elderly, sleep walking may be a symptom of an organic brain syndrome or REM behavior disorders.

When someone sleep walks, they may sit up and look as though they are awake while they are actually asleep. They may get up and walk around, or do complex activities such as moving furniture, going to the bathroom, and dressing and undressing. Some people even drive a car while they are asleep. The episode can be very brief (a few seconds or minutes) or can last for 30 minutes or longer.

Some people mistakenly believe that a sleep walker should not be awakened. It is not dangerous to awaken a sleep walker, although it is common for the person to be confused or disoriented for a short time when they wake up. Another misconception is that a person cannot be injured when sleep walking. Actually, sleep walkers are commonly injured by tripping and losing balance.

Sleep walking can occur at any age, but it happens most often in children aged 4 - 8. It appears to run in families.