Since humanity began communicating, mankind has asked, "why do people dream?" It's a question scientists are still sorting out. Dreams occur during one of five stages of sleep known as rapid eye movement stage or REM.
During this sleep stage, which happens about an hour and a half after falling asleep, the sleeper's eyes move rapidly back and forth. Breathing is shallow and irregular and blood pressure and heart rate both increase. In many respects, REM sleep is similar to being awake, but the body does not move.
When Dreams Occur
About one-fifth of all sleep occurs during the REM stage of sleep. During this time, scientists believe that one of the answers to the question of "why do people dream" is that dreaming helps facilitate necessary brain processing. With dreams or other altered states of consciousness, the brain is stimulated in the learning and memory regions.
According to a National Institutes of Health, animal studies indicate REM sleep is a time when the brain sorts and processes information acquired during the day. During this processing, the brain picks up old images and information, too, and reorganizes itself, rather like a filing cabinet. This reorganization is believed to present itself as dreams.
Nature of Dreams
Dreams can last anywhere from a few seconds to 15 or 20 minutes. Many dreams are strange and have no relation to anything that the dreamer understands. However, often components of dreams can be traced to daily routines or things the dreamer saw or did during waking hours.
Some dreams can appear quite vivid and are sometimes a symptom of a sleep disorder that causes a person to be overly sleepy during the day. The dreamer sometimes confuses these vivid dreams with reality because they seem so real.
When people dream, the body enters a state of paralysis that keeps the dreamer from "acting out" the dreams. Sometimes this mechanism malfunctions and people walk or talk in their sleep. These malfunctions, which are more common in children than in adults, are called parasomnias. They include sleep walking, sleep talking, confused arousals, sleep paralysis, acting out dreams, and night terrors.
People who are awakened frequently during their dream stages experience dream deprivation, which can result in increased tension and irritability, along with difficulty concentrating. Interrupted dreaming also has been shown to cause weight gain, feelings of emptiness, and hallucinatory tendencies.
A discussion of dreaming would not be complete without noting a different category of dreaming referred to as lucid dreams. A lucid dream is an intentional dream during which individuals are aware they are dreaming and seek to control the content, characters, and narrative of the dream experience. Some experts may refer to lucid dreams as a complex neurological occurrence that delivers an extraordinary experience for individuals.
Additional reading about dreaming and sleep can be found in the list of article links below.