The first stage of sleep is a very light sleep and only lasts between 5 and 10 minutes. In this stage, our brain activity powers down by about 50 percent, producing theta waves. These waves happen four to seven times per second. Theta waves are produced during active alert states. When we begin to fall into a deeper sleep we start to become relaxed and can experience hypnagogic imagery, which are strange images that go in and out of consciousness. In the first stage …show more content…
After returning to stage two the our brains shift to a more high gear, high frequency sleep, with low amplitude waves similar to those of wakefulness. During this stage we have an increased heart rate and blood pressure, along with rapid and irregular breathing. This stage consists of between twenty and twenty five percent of a night's sleep. After ten to twenty minutes of this REM sleep, they cycle begins again, moving back to the beginning stages of sleep and into the deeper sleep stages again. In a typical night we return to REM sleep five or six times. A majority of our dreams occur in REM sleep. Dreams in REM sleep are usually very emotional and illogical whereas dreams in non-REM sleep are shorter, thought-like and repetitive. The REM stage serves a critical biological function. When people are deprived of this stage of sleep they go into REM rebound meaning the amount and intensity of REM sleep