Sleepwalking is when someone gets up and moves around while still asleep. Their eyes might be open and they might even perform complex actions like walking down stairs, opening doors, or rearranging objects, but they're not fully awake or aware of what they're doing. A sleepwalker often won't remember their nighttime wanderings the next morning.

Sleepwalking happens during deep sleep, when the brain is partially active but the person isn't conscious. It's most common in children between ages 4 and 12, though some people continue sleepwalking into adulthood. Episodes usually last just a few minutes, though occasionally they go longer.

Despite what you might see in cartoons, sleepwalkers don't walk with their arms stretched out in front of them like zombies. They look and move almost normally, though their movements might seem a bit clumsy or confused. Waking a sleepwalker won't hurt them, but it might startle them badly.

The word can also describe going through motions without really thinking or being engaged, like when you say you were sleepwalking through a boring task. Scientists still don't fully understand why sleepwalking happens, but stress, exhaustion, and irregular sleep schedules can make episodes more likely.