Stages of Sleep As the issue of health becomes more important in our everyday lives, ways to stay healthy have been increasingly investigated. One of the easiest ways a person can stay healthy is to sleep. Too little or sometimes too much sleep can be unhealthy and at times dangerous. Before the beginning of sleep research in 1970 there was no rhyme or reason to why human beings slept other than being tired. One of the …showed first 75 words of 443 total…

…showed last 75 words of 443 total…in stage two. There is some low frequency and high amplitude waves called delta waves. Stage four is the deepest sleep of them all. Over fifty percent of delta waves. This is the stage of sleep that has the lowest level of arousal people normally experience. Usually sleepers take about thirty to forty minutes to go through the NREM stages when sleepers finish stage four, they go back through stages three, two and sometimes one.