How a Woman Could Sleepwalk for 9 Miles

— -- A Colorado woman told police she has no memory how she got 9 miles from her Denver home, even though she was found in her pajamas and with no shoes.

Taylor Gammel, 19, was missing for hours on Tuesday morning before she was found or rather "woke up" 9 miles from her home, according to the Jefferson County Sheriff's Office.

"She came out of a sleepwalking state, and she was on the side of the road and recognized where she was," Jefferson County Sheriff's Office public information officer Mark Techmeyer told ABC News.

Gammel was reported missing by her parents around 6 a.m. Tuesday, though she hadn't been seen since 10 p.m. the night before, when she went to bed.

Techmeyer said Gammel was wearing sweatpants, a T-shirt and socks when she was found. He said there's a chance that she might have been able to take a bus part of the way, but without an ID, a wallet or money, he doubts that was possible.

Dr. Shalini Paruthi, a board-certified sleep specialist and associate professor of pediatrics and internal medicine at St. Louis University, said Gammel's 9-mile walk is not unheard of.

"It’s a subconscious state, and for the most part [sleepwalkers] do look awake … They have their eyes open, and they have a glassy look to their eyes," she said. "They can do simple behaviors and walk down steps. They can do routine behaviors … Kids will urinate in the wrong place, or they wake up in the wrong place."

Paruthi said some people will even sleep eat or sleep drive without ever waking.

"This is something that can be so scary for the person when they find out what happened," she said.

Paruthi said that sleepwalking is most common in young children but that it can happen to people at any age. She said loud noises, sleep apnea or heartburn can cause a teen or adult to start sleepwalking.

She said it's key for patients with sleepwalking problems to take safety steps such as installing door or window alarms so that either they or their family members will be alerted if they try to make a break for it. She also said it's important for family members to lock up anything dangerous such as knives, guns and even car keys if a family member is sleepwalking around the house.

As for the urban legend that you should never wake a sleepwalker, Paruthi said it's usually safe to wake up a sleepwalker as long as it's gently. She did, however, emphasize that a sleepwalker can occasionally be violent upon waking.

"I think the most important thing is certainly realizing that there are safety measures that all family members can take," said Paruthi.