Each night people go through several cycles of non-REM and REM sleep. Sleepwalking (somnambulism) most often occurs during deep, non-REM sleep (stage 3 or stage 4 sleep) early in the night. Sleepwalking can occur at any age, but it happens most often in children aged 4 - 8 and appears to run in families. It can be effected by hormonal changes, stress, anxiety, diet and medication. I have always had parasomnia (unwanted actions during sleep) and vivid REM sleep dreams and realistic night mares but the sleep walking has been an on and off issue during my lifetime. I started as a child but that was only for a few years, from around 8-15 was not affected at all and during puberty it came back briefly. As an adult (from 19 to present) it generally only occurred at stages in my life when I was stressed about money or work. My mum has very strange vivid dreams and my dad has history of sleep walking too - the most famous was him trying to climb on-top of a wardrobe to escape aliens during a very stressful time in his life, I was very young and my brother was a very sick baby.
When people sleepwalk, they may sit up and look as though they are awake when they are actually asleep. They may get up and walk around, or do complex activities such as moving furniture, going to the bathroom, and dressing or undressing. Some people even drive a car while they are asleep - or in rare cases become violent. I can get very physically active during sleep but this due to vivid dreams, night terrors or nightmares and not related to sleep walking. Generally a sleep walker will use muscle memory to calmly do every day tasks, tasks they could literally do with their eyes closed or without thinking.
The episode can be very brief (a few seconds or minutes) or it can last for 30 minutes or longer. If they are not disturbed, sleepwalkers will eventually go back to sleep. Sleep walkers are vulnerable and suggestive, its easy to guide me back to bed. Its thought that sleep walking inspired the first voodoo stories of Zombi's - the walking dead. It actually your subconscious that does all the work whilst sleep walking, that is why you dont remember any of it, the part of you that makes you "you" is not actually present, a body without a soul if you like. Voodoo zombies were slaves to their mistresses and were very suggestive, slow and methodical in their tasks much like real sleep walkers.
Since I've been pregnant I was very worried about sleep walking, I was worried if I tripped or strained myself I would harm the baby. I've not hurt myself before but have gone out side and often move furniture or go about every day tasks. My husband sleeps like a log and doesn't wake up most of the time, I have tried shutting myself in with towels under the door - the idea is that my zombie brain can't work out why it wont open and I just got back to bed. We have bells on the bedroom door handle now, its not enough to wake Dave but for some reason it seems to work. Given time my mind will get used to the noise and it will stop working and we will have to think of something else. Its not enough to wake me up, it can be very traumatic for the dreamer and is much like coming up for air whilst drowning and seems to take a very long time - not a pleasant experience in the least.
I think the dog gets a bit confused by me walking about, if I spend too long roaming around Monty (our German Shepard dog) goes up stairs -which he is not allowed to do normally- and wakes up Dave my DH who then wonders where I am and comes to find me. Last week I woke myself up (doesn't usually happen) and the dog was laying on the stairs. I assume he'd gone to get DH and after finding him missing given up, Dave had been away with work. Around me were dozens of folded / screwed up bits of blank paper and some sticking out of the letter box, on inspection there was plenty of paper on the door stop too >_> I do worry myself sometimes.
Since being pregnant I often woke up craving burgers / junk food and meat quite a bit in the first trimester but now that has chilled out and I wake up in the night thinking about food. I cant go back to sleep before I've had a piece of toast or cup of tea and biscuit, so the dog must get thoroughly confused by my midnight snacks and sleepwalking. I do wonder if I give him commands in myself, I certainly tell him to be quite enough times in my waking hours!