How important is sleep to humans? A good night’s sleep is a vital and incredibly essential component to every human’s well-being. However, a lot can interfere with natural sleep patterns, such as eating, exercising, and dreams.
Oftentimes, sleep can be a state of change that is the cause of consciousness, characterized by certain brain lopes. Consciousness, a state of feeling awareness, including a person’s feelings or sensations, can have different levels of awareness during sleep. Some people are fully aware that their attention focuses on something conscious of that “something,” while others are on a different level. Sleep illustrates an altered state of consciousness.
Although sleep is a significant part of human behavior, it has been challenging to study. Researchers cannot ask a sleeping person to report their experience without first waking the person. Impossible! A sleep study was aided by the development of the electroencephalogram (EEG). This device records the electrical activity of the brain and uses small metal discs called electrodes that are attached to your scalp, which allow your brain cells to communicate the electrical impulses while you are asleep.
So the question is: Why do we sleep? Scientists and researchers are not sure why people sleep. Sleep is characterized by unresponsiveness to the environment and limited physical mobility. Some people believe that sleep is restorative; it allows people to “charge up their batteries.” These people believe that sleep is when the brain recovers from exhaustion and stress, while other people think it is a type of primitive hibernation: we sleep to conserve energy. Some suggest that sleep is an adaptive process; that is, in earlier times, sleep kept humans out of harm’s way at night when humans would have been most vulnerable. Still, other researchers believe we sleep to clear our minds of useless information, but some people believe we sleep to dream.
As you begin to fall asleep, your body temperature declines, your pulse rate drops, and your breathing grows slow and even. Gradually, your eyes close, and your brain briefly emits alpha waves. Your body twitches, your eyes roll, and visual images flash across your mind as you enter Stage I sleep, the lightest level of sleep. In Stage I sleep, your pulse slows a bit more, and your muscles relax, but your breathing becomes uneven, and your brain waves grow irregular. If you were awakened during this Stage, you would say that you were “just drifting.” This phase lasts for about 10 minutes and is marked by theta waves, which are of lower amplitude and frequency than alpha waves. Your brain waves will start to shift from low-amplitude, high-frequency waves to high amplitude, low-frequency waves - a pattern that indicates you have entered Stage II sleep. During Stage II sleep, your eyes start to roll very slowly from side to side, and about 30 minutes later, you drift into a deeper level Stage III sleep, and large-amplitude delta waves begin to sweep your brain every second or so.
At the later stages, Stages IV sleep is the deepest of all, and it is difficult to awaken a sleeper in this Stage. Large, regular delta waves indicate that you are in a deep sleep. If a loud noise or sudden movement awakens you, you may feel disoriented. Talking out loud or sleepwalking leaves no trace on the memory. Deep sleep is essential to your physical and psychological well being. Perhaps this is why people who can sleep only a few hours at a time descend rapidly into Stage IV and remain there for most of their naps. On average, a person spends about 75 percent of sleep time in Stages I through IV. However, something curious and strange happens. Your muscles are even more relaxed than before; your eyes begin to move rapidly as you enter a more active type of sleep called REM Sleep or rapid eye movement.
During REM Sleep, your pulse rate and breathing become irregular, and the levels of adrenal and sexual hormones in your blood rise - as if you were in the middle of an intensely emotional or physically demanding activity. Often, your face or fingers twitch, and the large muscles in your arms and legs are paralyzed. Your brain sends out waves that closely resemble those of a person who is fully awake. For this reason, REM sleep is called active sleep. Stages I through IV are sometimes referred to as NREM (non-REM) or quiet sleep because of the absence of rapid eye movement, which is accompanied by the slower pattern of brain waves. It is during REM sleep that almost all dreaming normally takes place. It can last from about 15-45 minutes, after which you retrace the descent of Stage IV and go through a cycle that lasts every 90 minutes or so.
What is a dream? Dreams are imaginable stories and images that our mind creates during our sleep. They can either be satisfied, miserable, or frightened.
We call the mental activity that takes place during sleep dreaming. Everybody dreams, although most people can recall only a few, if any, of their dreams. (However, in cultures where dreams are highly valued and talked about frequently, people remember their dreams almost every morning.) As the night wears on, dreams become longer and more vivid and dramatic, especially dreams that take place during REM Sleep. Because the amount of time spent in REM sleep increases during the night, the last dream is likely to be the longest and the one people remember when they wake up. People, however, can rarely recall more than 15 minutes of a dream when they are awakened. Researcher, William Dement, has found that after people have been deprived of REM sleep, they subsequently increase the amount of time they spend in REM sleep and that a certain amount of dreaming each night is necessary.
Regardless, when people are awakened randomly during REM sleep, they ask themselves what they had just been dreaming about. The dreams we remember and talk about “are more coherent, sexier, and generally more interesting,” said Wilse B. Webb. Often, sleep incorporates our everyday activities into our dreams. Researchers Hall and Van de Castle, who have recorded the content of thousands of dreams, have found that most occur in such commonplace settings as living rooms, cars, and streets. Most dreams involve either strenuous recreational activities or passive events such as sitting and watching. Contrary to popular beliefs, dreams do not occur in a split second; they correspond to a realistic time scale.
Some dreams are negative enough to be considered nightmares. Nightmares often have such a frightening quality that we awaken in the middle of them. The sense of dread in nightmares may be related to the intensity of brain activity and to the stimulation of those parts of the brain responsible for emotional reactions. The emotional response of dread may then influence the content of the dream.
Dreams have many interpretation ways that can be understood. Dream interpretations have been discovered dating back to 5000 B.C. Sigmund Freud, the first psychologist to study dreams, believed that no matter how simple or mundane, dreams may contain clues to thoughts, the dreamer is afraid to acknowledge them in their waking hours. Freud hypothesized that dreams express impulses and thoughts, often in highly symbolic form, that is unacceptable at the conscious level. The Inuit people of North America, like Freud, believe that dreams contain hidden meanings. They believe that when dreaming, people enter the spiritual world where they interact with those who have passed away. These departed souls help the living reflect on some current or future events.
Some social scientists, however, are skeptical of dream interpretations, such as Nathanial Kleitnam, one of the pioneers who discovered REM sleep, wrote in 1960: “Dreaming may serve no function whatsoever.” According to this view, the experience of a dream is simply an unimportant by-product of stimulating particular brain cells during sleep. One dream researcher, Cartwright, advocates a problem-solving theory about dreaming. His theory proposes that dreaming allows people a chance to review and address some of the problems they faced during the day. One theorist, Francis Cricks, believes that dreams are the brain’s way of “unlearning” or removing certain unneeded memories. In other words, dreams are a form of mental house-cleaning.
Lastly, dreams do not always occur at night while you sleep; it can also happen anytime during the day, called daydreaming. Daydreaming requires a low level of awareness and involves fantasizing or dreaming while you are awake. Usually, a person daydreams when they are in a situation that requires little attention or when they are bored. Daydreaming serves useful purposes such as reminding us of or preparing us for important things in our future. Daydreaming may also improve our creativity by generating thought processes. Some psychologists believe that daydreaming allows us to control our emotions.