Dreaming is the final stage in the sleep cycle.
Dreams are highly beneficial for your brain and body. While you sleep dreamlessly, your body rests and regains energy. While you dream, your brain does the same. During dreams, the brain consolidates information learned throughout the day. Many people even solve problems in dreams that they hadn't found solutions to in their waking hours. Dream deprivation has many negative effects on the brain and the body, including chronic lethargy, reduced productivity, increased sensitivity to pain and poor verbal communication.
The Sleep Cycle
There are five stages of sleep as indicated by EEG recordings, which measure brain activity. The first four steps are dreamless. In stage 1, you transition between wakefulness and sleep. Stages 2 through 4 indicate progression into sleep, with respiration, heart rate, temperature, and muscle tension gradually declining. Scientists measure the stages of sleep by the ratio of sleep spindles, which are high-frequency bursts of brain activity, and delta waves, which are high-amplitude brain waves that indicate deep sleep. In the fifth stage of sleep, you dream. This sleep cycle is repeated up to six times within an eight-hour block of sleep.
REM Sleep
The fifth stage of sleep is called REM sleep, which stands for Rapid Eye Movement. REM sleep typically occurs about 90 minutes after the onset of sleep. In each cycle of stages, length of REM sleep increases, often up to an hour of dreaming in the final cycle before waking. Infants and small children spend the majority of their sleep cycle dreaming, but as humans age, the need for REM sleep decreases.
Physical Changes
Dreaming is called REM sleep because while you dream, your eyes often move rapidly within their sockets from side to side. You dream during REM sleep due to heightened brain activity during this stage. Respiration and heart rate may become erratic during this dreaming stage. While your dreams may consist of you running away from a monster or meeting a friend you've been thinking about lately, your body remains immobile because with the onset of dreaming, an area in the brain called the pons sends signals to the spinal cord to shut down the neurons there. This prevents the neural impulses produced during dreams from reaching the rest of the body.
Dream Composition
Dreams are composed of the thoughts, images and emotions experienced during REM sleep. Your brain creates a narrative out of these elements of dreaming that becomes connected and somewhat understandable. Many dream interpreters suggest that most dreams contain elements of day-to-day life in alternate forms. For example, individuals may be able to identify metaphors and themes in their dreams that relate to events occurring in their lives.
Tags: brain activity, sleep cycle, stage sleep, brain body, called sleep