Sleep and dreaming. EnglishDrills.org illustration.
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Every night, most people spend part of their sleep dreaming. Dreams can feel exciting, strange, frightening or completely ordinary. Scientists still do not know exactly why we dream, but they have learned a great deal about when dreams happen. Vivid dreams are especially common during a stage of sleep called REM sleep. REM means rapid eye movement because the eyes move quickly behind closed eyelids. During this stage, the brain is very active even though most of the body's large muscles are temporarily relaxed. Researchers think dreams may be connected with memory, emotions and learning. The brain may be sorting through experiences from the day and linking new information with older memories. However, there is no single explanation that answers every question about dreaming. People can also dream during other stages of sleep, and many dreams are forgotten within minutes of waking. Keeping a notebook beside the bed can help people remember them. Dreams remain one of the most fascinating parts of sleep because they turn thoughts, memories and feelings into stories that can seem real while we are asleep.
