What is REM sleep?
The period of REM sleep is marked by extensive physiological changes. These include: • Accelerated respiration • Increased brain activity • Eye movement • Muscle relaxation Usually, REM sleep occurs 90 minutes after sleep onset. The first period of REM typically lasts 10 minutes, with each recurring REM stage lengthening, and the final one lasting an hour. Polysomnograms (sleep readings) show wave patterns in REM to be similar to stage 1 sleep. In people without sleep disorders, heart rate and respiration speed up and become erratic during REM sleep. The face, fingers, and legs might twitch. Intense dreaming occurs during REM sleep as a result of heightened cerebral activity, but paralysis occurs simultaneously in the major voluntary muscle groups. REM is a mixture of encephalic (brain) states of excitement and muscular immobility. For this reason, it is sometimes called paradoxical sleep. The percentage of REM sleep is highest during infancy and early childhood. During adolescence and
REM, or rapid eye movement sleep, is the fifth of the five stages of sleep most people go through each night. REM is characterized by quick movements of the eyes during sleep, which is what gave this stage its name. What exactly goes on during REM? And how is it different from the other stages of sleep? The first stage of sleep is very close to waking. During this stage, the body gradually relaxes. There may be some eye movement, but not to the extent that there is during REM sleep. If someone is awakened during this stage, he might not even be aware that he had been asleep. The second stage is a time of light sleep, when muscles alternately relax and contract. Body temperature decreases. The heart rate slows down. The third and fourth stages of sleep are times of deep sleep, with stage four being the deepest. The sleeper will alternate between stages three and four. During these stages, the sleeper is quite still with very rhythmic brain activity. These stages are called delta sleep.
REM sleep is rapid eye movement sleep. During REM sleep, one breathes faster and has a higher heart rate than during NREM (nonrapid eye movement) sleep. Also during REM sleep, one’s eyes move and hands and feet twitch. A sleeping person has dreams—often with elaborate storylines—when experiencing REM sleep. There are usually four to five periods of REM sleep per night, each period lasting from five minutes to an hour. Durations of REM sleep periods grow longer as sleep continues. It has been shown that dreaming is an important component of sleep, although it is not completely understood why. One theory states that during dreams, the brain sorts through the information it has picked up during the day and discards that which it deems unnecessary. Another theory is that dreams help us handle emotional stress by creating scenarios we must work through. Regardless of their function, most people who are…
Usually, REM sleep occurs 90 minutes after sleep onset. The first period of REM typically lasts 10 minutes, with each recurring REM stage lengthening, and the final one may last up to an hour. Polysomnograms show brainwave patterns in REM to be similar to that recorded during wakefulness. In people without sleep disorders, heart rate and respiration speed up and become erratic during REM sleep. During this stage the eyes move rapidly in different directions. Intense dreaming occurs during REM sleep as a result of heightened brain activity, but paralysis occurs simultaneously in the major voluntary muscle groups. REM is a mixture of encephalic (brain) states of excitement and muscular immobility. For this reason, it is sometimes called paradoxical sleep. The percentage of REM sleep is highest during infancy and early childhood. During adolescence and young adulthood, the percentage of REM sleep declines. Infants can spend up to 50% of their sleep in the REM stage of sleep, whereas adult
