Sleep is a process where our bodies have a chance to rest, relax, and repair itself. Sleep gives our brains a chance to process and consolidate new information, and our bodies to repair injuries, ailments, and regulate growth and appetite. Here, you will learn about the different stages of sleep, how they contribute to personal well-being, and determine how much sleep YOU personally need for optimal wellness.
Stages Of Sleep
Human sleep has been described as a succession of 5 recurring stages: 4 non-REM (without rapid eye movement) stages and the REM stage. A 6th stage, waking, is sometimes included.
Stage 1 is often described as first in the cycle. The eyes are closed, but if aroused from sleep, a person may feel as if he/she has not slept. Stage 1 may last for 5-10 min.
Stage 2 is a period of light sleep, when a person becomes disengaged. The heart rate & breathing slow down, and the body temperature decreases as the body prepares to enter deep sleep.
Stages 3&4 are deep sleep stages, with stage 4 being more intense than 3. During these stages, the blood pressure drops, breathing is slower, and muscles relax. the body’s energy level is being restored, and hormones are released.
REM sleep is distinguished by its characteristic rapid eye movements. In this stage of sleep, heart rate & respirations speed up and become erratic, while the face fingers, and legs may twitch. Intense dreaming occurs during REM, as a result of heightened brain activity, but paralysis occurs simultaneously in the major voluntary muscle groups. It is generally thought that REM-associated muscle paralysis is meant to keep the body from acting out the dreams that occur during this intensely cerebral stage. The first REM period typically lasts 10 minutes, with each recurring REM stage lengthening, and the final one lasting an hour.
REM sleep consists of about two hours a night, while non-REM sleep lasts about four to six hours.
Sleep quality changes with transition from 1 sleep stage into another. The signals for transition between the stages are mysterious. It is important to remember that these stages are discreetly independent of one another, each marked by subtle changes in bodily function and each part of a predictable cycle whose intervals are observable.
The sleep cycle (stages 1-5) is repeated 5 or 6 times during the night. Each cycle takes about 90 min.
Since the earliest of recorded histories, people have theorized about the function and meaning of dreams. Answers came largely from the spirit world until Aristotle and Plato developed the drive related hypothesis that was later expanded on by the European psychoanalysts of the 19th and 20th centuries. this hypothesis defines dreaming as a way to act out unconscious desires in a safe or “unreal” setting, presumably because to do so in reality would be unacceptable or even detrimental. But even in the 21st century we still are not sure why we dream. the only way to study dreams is to ask the dreamer. However, one thing we know for sure is that dreaming is something that the vast majority of humans do every night of their lives.
Some researchers think dreaming might have evolved for physiological reasons. There is a great deal of neuronal activity occurring while we sleep, especially in REM, and it has been suggested that dreams may just be a meaningless by-product of this biological function. Another theory of dreaming is put forth by Rosalind Cartwright PhD, Professor and Chairman, Department of Psychology at Rush University Medical Center in Chicago. Dr. Cartwright believes that dreams are the mechanism whereby the brain incorporates memories, solves problems, and deals with emotions. In this way, she maintains, dreams are essential for our emotional health.
A person can dream during both non-REM and REM sleep cycles. Non-REM dreams consist of brief, fragmentary impressions and are less likely to involve visual images compared to REM sleep, and are more frequently forgotten. Non-REM dreams are like thinking about something during the day for a brief period of time, while REM dreams are comparable to thinking deeply about something.
Dream Interpretation is the process of assigning meaning to dreams. In many ancient societies, such as those of Egypt and Greece, dreaming was considered a supernatural communication, or a means of divine intervention, whose message could be unravelled by people with certain powers. In modern times, various schools of psychology and neurobiology have offered theories about the meaning and purpose of dreams.