Could you be lying down in bed at night and then getting back up on your feet without even knowing it?

A new study in the journal Neurology finds that more people may be sleep walking than experts previously thought. Nearly 20,000 adults answered a survey about their sleep habits and their mental and physical health. Nearly 30% said they had sleepwalked at some point in their lifetime and about 3.6% said they had sleepwalked in the previous year.

Some people were more likely to sleepwalk more than two times per month, including people with obstructive sleep apnea, insomnia, major depression, obsessive-compulsive disorder and alcohol dependence or abuse as well as those who used over-the-counter sleeping pills and certain types of anti-depressants.

According to the National Sleep Foundation, since sleepwalking can lead to injuries, waking up people who are roaming around at night may protect them from harm.