When we are sleeping, our brain secretes chemicals to our body that causes them to become immobile. This protects you from acting out your dreams and hurting yourself. For example, imagine dreaming that you are running and you try to act that out while you’re asleep. You’re going to get injured by either running into the wall or stairs. Hence, our brain protects us while we sleep by making us incapable of moving.
However, Sleepwalking, also known as somnambulism, is a sleep disorder belonging to the parasomnia family. Sleepwalkers arise from the slow wave sleep stage in a state of low consciousness and perform activities that are usually performed during a state of full consciousness.