The Seven Stages of Sleep

On average, it's about 90 minutes where we go through all the stages of sleep. There are three kind of gross states of sleep, but people have characterized as many seven sub states of sleep that happen throughout the night. We start to get sleep spindles and those K complexes in our brain during stage two which is when we're fully unconscious. It's also a state where if there are portions of your brain that are awake, you could do things like sleepwalking or sleep talking.