Why do people sleepwalk?

Have you ever woken up to find food crumbs or your sheets, even though you don’t remember waking up to snack? What about waking up on the living room sofa when you vividly remember going to sleep in your bed? You may be a sleepwalker.

Sleepwalking, also known as somnambulism, is a sleep disorder that involves waking up and walking around while in a state of sleep. A sleepwalker might even perform more complicated activities such as cooking, eating, getting dressed, and driving. In some rare cases, a sleepwalker may even engage in unusual behaviours such as climbing off the window or urinating in the wardrobe.

If you’ve experienced sleepwalking, you’re not alone; 6.9 per cent of people in the general population report experiencing at least one episode of sleepwalking in their life. However, the prevalence of sleepwalking is higher in children than adults. Only 1.5 per cent of adults experience sleepwalking episodes beyond their childhood years.

Sleepwalking often happens during the first few hours after falling asleep. Although the name suggests walking around, not all sleepwalkers walk during their episodes. Some might just sit up or stand up in bed.

The sleepwalker might move around for a few seconds or as long as half an hour. Although their eyes might be open and they act as if they’re awake, they’re actually asleep. In fact, sleepwalking occurs in the deepest part of non-rapid eye movement sleep. They tend to go back to bed on their own and wake up with no memory of sleepwalking.

Sleepwalking tends to run in families, although the exact reason for this is yet to be known. Compared to children with no family history of sleepwalking, children with one parent who has experienced sleepwalking are three times more likely to be sleepwalkers. This is according to a study published in the journal JAMA Pediatrics in 2015.

In most cases, sleepwalking is harmless and tends to resolve itself. But in a small number of cases, the sleepwalker might pose danger to themselves and others.

In a 2013 French study that involved 100 patients with history of repeated sleepwalking, 57.9 per cent had been injured or had injured someone else during an episode. Injuries resulted from activities such as falling down the stairs, bumping into objects, or being violent to bed partners.

Sleepwalking might also be a symptom to a more serious health problem. Here are some of common causes for sleepwalking:

Sleep deprivation

One of the most common causes of sleepwalking is lack of adequate sleep. A study published in 2008 by the University of Montreal found that sleep deprivation can precipitate sleepwalking in predisposed individuals.

The researchers evaluated 40 individuals who were suspected sleepwalkers. The subjects’ sleep was monitored in an initial all-night assessment.

In a subsequent visit, they were kept awake for an entire evening and only allowed to sleep after 25 hours of being awake. During their usual baseline sleep, only half of the subjects exhibited symptoms associated with sleepwalking. After being sleep deprived, 90 per cent of the patients exhibited sleepwalking behaviours.

“Sleepwalkers are advised to maintain a regular bedtime and avoid sleep deprivation if they wish to steer clear of somnambulism,” said one of the researchers.

Physical or emotional stress

Sleepwalkers are likely to have episodes during periods of stress. Maybe they have a big test coming up or are working on an important project. In some cases, the source of stress might be simply about being in unfamiliar environment.

A study that involve 193 patients in a sleep clinic found that patients were more likely to experience sleepwalking episodes after going through stressful events during the day. To reduce your daily stress, you could try regular exercise, breathing exercises, yoga, and practicing mindfulness.

Breathing disorders

Being unable to breathe properly during sleep might trigger sleepwalking episodes. Obstructive sleep apnea, where one stops breathing for short periods while asleep, is a top culprit.

A 2009 study from Loyola University Chicago Stritch School of Medicine found that nearly one in 10 patients with obstructive sleep apnea also experience “parasomnia” symptoms, which include sleepwalking, hallucinating, and acting out their dreams. In addition to triggering sleepwalking, severe sleep apnea is also known to cause daytime fatigue, high blood pressure, stroke, and heart disease.

Asthma is also known to cause sleepwalking, especially in children. A drug known as montelukast, which is used to treat asthma has also been associated with causing sleepwalking in some children.

Gastroesophageal Reflux Disease (GERD)

When one is suffering from GERD, the contents of their stomach backup through the oesophagus. This causes an uncomfortable burning sensation and chest pain. For most people, the symptoms of GERD tend to worsen at night.

People who suffer from GERD are more prone to sleep disorders including sleepwalking. Due to interfering with sleep, GERD might lead to long-term exhaustion, which makes one more vulnerable to sleepwalking episodes.

Restless Leg Syndrome

Although the subject is still being debated by researchers, some studies show that people who suffer from restless leg syndrome (RLS) are more likely to experience sleepwalking.

Restless leg syndrome, which is also known as Willis-Ekbom disease, is a nervous system disorder that causes one to have an irresistible urge to move their legs. This typically occurs when the person is sitting or lying down. It might also cause trouble sleeping, which in turn triggers sleepwalking.

The medication used to treat restless leg syndrome has also been associated with causing sleepwalking.

Parkinson’s Disease

Parkinson’s Disease is a degenerative neurological disorder that affects one’s ability to move. Its symptoms include tremors during rest, rigidity in the joints, poor coordination, and mental fogginess.

As Parkinson’s disease progresses, it can affect the parts of the brain that control sleep. Usually, your brain paralyzes some of your muscles to keep you from acting out your dreams during sleep.

In individuals suffering from Parkinson’s disease, this paralysis might not happen effectively. This leads to sleepwalking and other sleep disturbances.

Certain medications

As indicated in the case of medication to treat asthma and restless leg syndrome, some drugs might cause people to sleepwalk. Even some sleep-inducing drugs, such as zolpidem (often sold under the names Ambien and Edluar) are known to trigger sleepwalking.

Other drugs that might cause sleepwalking include antidepressants, anti-psychotics, and beta-blockers used to treat heart disease and anxiety.