Someone answers a question in the middle of the night and remembers nothing in the morning. A child gets out of bed, walks through the house with open eyes, and returns to sleep as if nothing happened. Sleep talking and sleepwalking belong to the strangest things the human night produces — and, contrary to what most people assume, they usually have nothing to do with dreams.

Not dreams, but deep sleep

Both happen mostly in deep sleep, in the first hours of the night — not in REM, where dreams live. In REM the body is paralysed precisely so that we cannot act out our dreams; a sleepwalker is not chasing anything from a dream but is caught between states, with the body awake and the mind asleep. That is why sleep talkers speak in fragments that rarely make sense, and why a sleepwalker recognises no one and remembers nothing. About one in twenty adults talks in their sleep, and up to one in five children sleepwalks at some point — most outgrow it.

What brings it on

The usual triggers are lack of sleep, fever, stress, alcohol, irregular hours and, in children, simply an immature nervous system. Family history matters more than anything: sleepwalking runs in families. Episodes cluster in periods of pressure, which is why students, new parents and shift workers report them most.

What folk tradition made of it

Before there were sleep laboratories, a person walking at night was believed to be led by the moon — hence the old word for it in many languages. Sleep talk was treated as speech from another realm, and it was considered dangerous to wake the walker, whose soul was thought to be away. The dream dictionaries turn this around neatly: dreaming that you are talking in your sleep points to a secret that will not stay hidden much longer, while dreaming of a sleepwalker warns of moving through life on autopilot.

What to do

Do not wake a sleepwalker abruptly — that old advice is half right, not because of any harm to the soul, but because a confused waking is unpleasant. Guide them gently back to bed instead. Make the home safe: lock outer doors, block the stairs, keep the bedroom floor clear. Regular sleep hours and less alcohol reduce episodes markedly. See a doctor if episodes involve leaving the house, injury, or begin for the first time in adulthood.