Stages Of Sleep

Five Stages of Sleep You Should Know About

Regular sleep passes through five stages of sleep. Each stage is detected by the electrical activity in the brain measured by electroencephalogram (EEG). People go through the first stage as they lie down in bed, steadily growing more tired, feeling relaxed and closing their eyes. At this point, alpha waves start to appear in the brain. This marks the first of five stages of sleep.

Stage 1: This stage is a transitional stage from being awake to falling asleep. After a few minutes, the heart rate is lowered, brain waves slow down, breathing becomes regular and slow and muscles relax. People usually spend from five to ten minutes in stage one and move on to stage two. Stage 1 takes about 5% of the entire sleeping time.

Stage 2: Stage two is marked by the emitting of delta waves with "spindles and K-complexes" in EEG measurement. K-complexes are a sudden movement in brain waves, and spindles are like small, rapid moving brain waves. Average, healthy people spend 50% of their sleep in this stage. People become almost unaware of their environment and surroundings. The first two stages of sleep are like transitional stages into real sleep and they last about half an hour then enter into Stage three.

Stage 3: Brain starts to emit low frequency and high voltages waves: delta and theta waves. 7% of sleep is spent in this stage.

Stage 4: This is the deepest stage out of all the stages of sleep. As the theta waves disappear, people start to have a regular heartbeat, relaxed muscles, slow respiratory rate and low blood pressure. When they are awakened in the middle of this stage, they get confused with the outside surrounding making it hard for them to make quick reactions and judgments. Your body lets out growth hormones during this stage, motivating growth and repairing the muscles. Average adults spend about 11% in this sleep and it is important that you get a good stage 4 sleep.

Stage 5(REM sleep): During this stage, people move their eyes very rapidly, hence the name REM (rapid eye movement). Amazingly, the blood pressure, heartbeats, pulse and blood flows to the brain increase and become irregular. EEG readings show that waves are slow and still as if they are paralyzed. The increase in brain activity lets people dream and explore their subconscious minds enhancing brain repair and growth. REM sleep occurs after about 90 minutes of sleep.

After stage 5, the cycle repeats itself from stage 2 every 90 to 100 minutes. Most people make transitions through these stages of sleep about 4 or 5 times before they wake up.

And be sure to check out our pages about Sleep Disorders, Sleeping Pills, Sleep Problems, Sleep Aids, and Lack Of Sleep elsewhere on this site.