Up to 15 percent of adults occasionally get up and amble around the house in their sleep. In children, the number is even higher. No one knows what makes some sleepers wander, but stress and disturbed sleep are often factors. So is genetics: Close relatives of sleepwalkers are 10 times more likely to sleepwalk than the general population.
You won’t see sleepwalkers shuffling around, arms outstretched; many navigate their rooms with ease and are capable of opening doors and moving furniture. And while waking a sleepwalker won’t do them any harm, sleepwalking itself can be dangerous. One study published in 2003 in the journal Molecular Psychiatry found that 19 percent of adult sleepwalkers had been hurt during their nocturnal forays. Falling is the biggest danger, so if you’ve got a sleepwalker in your house, experts recommend you move the electrical cords and steer your somnambulist away from stairs.