Sleepwalking happens when part of your brain wakes up while the rest stays asleep. During an episode, brain imaging shows that the brainstem and cerebellum (which control movement and basic motor functions) are active, while the cerebral cortex (responsible for awareness, decision-making, and memory) remains in deep sleep. This split explains the hallmark features of sleepwalking: you can navigate a room, open doors, even hold a conversation, yet have no awareness of what you’re doing and little or no memory of it afterward.
About 5% of children and 1.5% of adults sleepwalk in any given year. Most children outgrow it by adolescence, but for some people, episodes persist or even start for the first time in adulthood. The causes range from genetics and sleep deprivation to medications and other sleep disorders.
What Happens in the Brain During an Episode
Sleepwalking occurs during the deepest stage of non-REM sleep, typically in the first third of the night when deep sleep is most concentrated. Normally, transitions between sleep stages are smooth. In sleepwalkers, something disrupts that transition: the body shifts toward waking, motor systems activate, but the parts of the brain responsible for conscious thought and memory stay offline.
The result is a person who can perform complex physical actions (walking, eating, rearranging furniture) while being essentially unconscious. Their eyes may be open with a blank stare, they’re difficult to wake, and if you try to talk to them, responses are slow or incoherent. After the episode ends, they typically return to bed or can be guided back, and they wake the next morning with no recollection of what happened. Some people recall a single fragmented image, like a snapshot from a dream, but nothing more.
Genetics and Family History
Sleepwalking runs strongly in families. If one of your parents has a history of sleepwalking, you’re about six times more likely to sleepwalk than someone whose parents never did. The trait appears to involve multiple genes rather than a single one, which is why it doesn’t follow a simple inherited/not-inherited pattern. Twin studies consistently show higher rates in identical twins compared to fraternal twins, reinforcing that biology plays a significant role beyond shared environment.
Having the genetic predisposition doesn’t guarantee you’ll sleepwalk, though. It lowers the threshold, making your brain more susceptible to the partial arousals that trigger episodes. Whether those episodes actually happen often depends on other factors layered on top of that baseline vulnerability.
Sleep Deprivation and Irregular Schedules
Not getting enough sleep is one of the most reliable triggers. When you’re sleep-deprived, your body compensates by spending more time in deep sleep during the next opportunity. More time in deep sleep means more chances for the kind of partial arousal that produces sleepwalking. This is why episodes often cluster during stressful periods, schedule changes, jet lag, or any situation that disrupts your normal sleep pattern.
For children, this connection is especially relevant. Irregular bedtimes, missed naps, or late nights can increase deep sleep pressure and make episodes more frequent. Parents who notice a pattern between late bedtimes and sleepwalking episodes are often seeing this mechanism in action.
Alcohol and Sedatives
Alcohol has a deceptive effect on sleep. It initially acts as a sedative, helping you fall asleep faster, but it fragments sleep later in the night and causes a small but measurable increase in deep sleep early on. That combination, more deep sleep plus more fragmented arousals, creates ideal conditions for sleepwalking in someone who’s already predisposed.
The effect isn’t limited to heavy drinking. Even moderate alcohol consumption close to bedtime can shift sleep architecture enough to trigger an episode in a susceptible person.
Medications That Can Trigger Episodes
A systematic review identified 29 medications linked to sleepwalking, falling mainly into four categories: sleep aids that act on the same brain receptors as benzodiazepines, antidepressants (particularly those affecting serotonin), antipsychotics, and beta-blockers used for blood pressure or heart conditions.
The strongest evidence points to zolpidem (a widely prescribed sleep medication) and sodium oxybate (used for narcolepsy). Both enhance deep sleep while simultaneously making the brain more prone to partial arousals, a problematic combination. Beta-blockers like propranolol have also been implicated in case reports, including one patient who fractured a leg during a sleepwalking episode attributed to the medication. If you’ve never sleepwalked before and episodes begin after starting a new medication, that timing is worth noting and discussing with whoever prescribed it.
Sleep Apnea as a Hidden Trigger
Obstructive sleep apnea, where breathing repeatedly stops and restarts during sleep, can trigger sleepwalking through a specific mechanism. Each time breathing pauses, blood oxygen levels drop, and the brain initiates a brief arousal to restart breathing. These micro-arousals happen dozens or even hundreds of times per night in severe cases. In someone genetically prone to sleepwalking, any one of those arousals can become a full sleepwalking episode instead of a simple return to normal sleep.
This connection matters because treating sleep apnea (usually with a device that keeps the airway open during sleep) can eliminate sleepwalking episodes entirely in these cases. Adults who develop new-onset sleepwalking, especially if they also snore heavily or feel exhausted despite sleeping enough hours, may have undiagnosed sleep apnea driving the episodes.
Other Common Triggers
Several additional factors can provoke episodes, particularly when they overlap:
- Fever and illness: Elevated body temperature during infections increases deep sleep and lowers the arousal threshold, which is why children often sleepwalk during febrile illnesses.
- Stress and anxiety: Emotional stress fragments sleep and increases the frequency of partial arousals throughout the night.
- Full bladder: The physical sensation of needing to urinate can act as an internal arousal cue, prompting a partial awakening that turns into sleepwalking rather than full consciousness.
- Noise and environmental disruption: External stimuli like a slamming door, a pet jumping on the bed, or a partner’s movement can trigger the incomplete arousal that starts an episode.
In practice, sleepwalking episodes often result from multiple triggers stacking together. A person with a family history who stays up late, has a glass of wine, and sleeps in an unfamiliar environment has compounded their risk in several ways at once.
Making Your Home Safer
If you or someone in your household sleepwalks regularly, simple changes to your environment can prevent injuries. Sleepwalkers can trip over furniture, fall down stairs, walk into glass doors, or handle sharp objects without any awareness of the danger.
- Block stairways: Use baby gates or similar barriers at the top and bottom of stairs.
- Remove tripping hazards: Low tables, rugs, power cords, and clutter on the floor are fall risks for someone navigating with no conscious awareness.
- Protect windows and glass doors: Replace glass panels with break-resistant material, or at minimum keep windows locked.
- Set up alerts: Motion-sensitive bells or alarms on bedroom doors can wake the sleepwalker or alert others in the household.
- Clear breakable objects: Lamps, glass decorations, and anything that could shatter should be moved away from common walking paths.
Keeping a consistent sleep schedule, avoiding alcohol close to bedtime, and managing stress can reduce episode frequency. For children, ensuring adequate total sleep and a regular bedtime routine addresses the most common trigger directly. When episodes are frequent or involve dangerous behavior, a sleep specialist can evaluate whether an underlying condition like sleep apnea is contributing and whether targeted treatment could help.