Why do people sleepwalk ?

According to the website of  'how stuff works.com', sleepwalking is an intriguing phenomenon. How does it happened (performing physical feats), when you're sleeping. How can a person be unconscious but still coordinate his, or her limbs to walk, talk and, to some extent ... even drive !
Also known as somnambulism, it is classified as an abnormal behaviour during sleep. Sometimes, it may includes bed-wetting and teeth grinding too. Just imagine how complex our brains are and how many tasks it performs. Besides enabling ones to breath, your heart to beat, and recording all the memories of your life ... it also enables you to laugh, cry, love and converse. But, what makes a sleeping body rise ? People used to think that sleepwalkers were acting out their dreams and subconscious desires and fears. Take Shakespeare's Lady Macbeth, who during the day conceals the depth of her treachery, but at night in her sleep confesses her guilt.

Sleepwalking episodes can last from a few seconds to half an hour. Such persons will usually have glassy-looking eyes and blank expressions on their faces. They might look awake but act clumsy. They are capable of performing a variety of activities, from simply getting up and walking around the room ---> to driving a car, or playing an instrument. They occured mostly in children. Individual sleepwalker behaved in their own ways, such as some kids are found wandering on the front lawn, or they walked down the street in their pajamas. However, as time goes on ... kids tend to grow out of it. The adult population of sleepwalkers is lesser. Sleepwalking often runs in families and occurs more often in boys than in girls.
The question is ---> why do we get up and walk around in the middle of the night ?

In fact, no one knows exactly why people sleepwalk. People used to think that sleepwalkers acted out their dreams. It has nothing to do with epilepsy, hysteria, dissociative disorders, or any other complications. Nonetheless, mental health professionals defined sleepwalking as a "disorder of arousal," which means that something triggers the brain into arousal from deep sleep. This means, the person is in a transition state between sleeping and waking.

Most adult sleepwalkers also sleepwalked during their childhood. It rarely begins in adulthood except as a symptom of other disorders. Children tend to sleepwalk more when they are overly tired, or stressed. The same factors also affect adults (certain medicines, alcohol and fever illnesses). If your child is sleepwalking, he, or she will probably either grow out of it, or can be helped by a regular sleep schedule and some stress reduction. If you're an adult and start sleepwalking, it might be a good idea to talk to a doctor. Otherwise, it should be considered as a harmless 'behaviour' and it will take its own pace to grow out of it.