Sleepwalking, or somnambulism, is a common parasomnia involving complex motor behaviors performed while technically asleep. Observers often follow the advice: do not wake them up. While myths suggest this could cause a heart attack or brain damage, the true reason is rooted in the neurobiology of the sleep state and the body’s reaction to sudden, forced wakefulness. Understanding this science explains why a gentle approach is the best response.
The Confused State of Sleepwalking
Sleepwalking episodes typically arise during the deepest stage of non-rapid eye movement (NREM) sleep, known as N3 or slow-wave sleep, usually within the first few hours after falling asleep. This state is one of partial arousal, where different parts of the brain are in distinct states. Regions controlling motor function, such as the motor cortex, become partially active, allowing for movement and other actions.
Meanwhile, areas responsible for conscious thought, judgment, and memory remain asleep. This creates a dissociated state, meaning the person is neither fully awake nor fully asleep. Because the brain’s executive functions are offline, the sleepwalker has impaired awareness, little responsiveness to external stimuli, and usually no memory of the event once they are fully awake.
Why Sudden Arousal Creates Danger
The primary danger of abruptly waking a sleepwalker is not physical harm to internal organs but the extreme confusion and panic that results. Forcing a person from deep NREM sleep into full consciousness causes a state known as confusional arousal or severe sleep inertia. This sudden shock triggers an immediate, exaggerated fight-or-flight response.
The sleepwalker’s brain, already compromised, perceives the rapid awakening as a threat. They find themselves in an unexpected location, often mid-action, with no memory of how they got there, leading to intense disorientation and fear. This rush of adrenaline causes them to act on instinct, which can manifest as either fleeing the situation or lashing out defensively at the person who startled them.
Because their judgment is severely impaired, a startled sleepwalker may attempt to run, jump, or struggle, significantly increasing the risk of serious injury, such as falls down stairs or through windows. While myths about heart attacks are untrue, the resulting panic and confusion pose a risk of accidental physical trauma to the sleepwalker or the intervening person. The goal is to avoid the shock of sudden arousal and the subsequent defensive reaction it provokes.
How to Safely Intervene
When encountering a sleepwalker, the first priority is maintaining a safe environment and a calm demeanor. Clear any immediate obstacles, such as furniture or loose items, from their path to prevent tripping. Directly confronting or physically restraining a sleepwalker should be avoided, as this can exacerbate their confused state and trigger a defensive reaction.
The safest approach is to gently guide the person back toward their bed. This can be done using a soft, soothing voice to speak their name or by offering gentle physical guidance, such as placing a hand on their back or arm. The aim is to steer them toward the safety of their room without achieving full wakefulness.
If they are in an immediately perilous situation, such as near a staircase or an open door, a slightly firmer verbal intervention may be necessary. This should still be done gently to minimize startling them. Once the individual is safely back in bed, they should be allowed to settle back into sleep naturally. They will likely not remember the episode in the morning.