Adults typically need seven to eight hours of sleep each night in order to function optimally. Additionally, it is important that we spend an adequate amount of time in each of the sleep stages. Most adults spend anywhere from 90 to 110 minutes in each stage of sleep. Children up to ten years of age spend less time in each stage than adults do. We cycle through each sleep stage, eventually starting over at stage one and finally progressing to REM sleep.
Stage 1
The first one to one and a half hours of sleep is known as stage 1. We can be awakened very easily during this stage.
Stage 2
During stage 2 we begin to sleep heavier and our brain waves are slower with occasional bursts of activity. We spend between one and a half to two hours in this stage.
Stage 3
During stage 3 we fall into a deep sleep, otherwise known as delta sleep. It becomes much harder to awaken someone during this sleep stage. It is in this stage of sleep that we have dreams. There is no eye movement, no muscle activity and our limbs are temporarily paralyzed. Children may have nightmares, wet the bed or walk in their sleep during stage 3. We then progress to the final stage of sleep, known as REM.
REM (Rapid Eye Movement)
Rapid eye movement or REM is the final stage of sleep. In this stage our breathing becomes more rapid, there are quick movements of the eyes, and our face and fingers twitch. Our heart beat increases and our blood pressure rises, although this may not happen to everyone. Our breathing becomes shallow and irregular. Dreams that occur during the REM stage may be remembered, while those that occur during stage 3 are difficult to recall.