Stage 4. apex:)
Delta
Stage 4 sleep. Stage 3 also often emits delta waves.
Delta Waves (APEX)
Delta waves
The brain wave associated with deep sleep is called delta waves. These slow brain waves are characteristic of the deepest stages of non-rapid eye movement (NREM) sleep. Delta waves are most prominent during the restorative stage of sleep known as slow-wave sleep.
There are four stages of sleep: 1) Stage 1 is characterized by theta waves, 2) Stage 2 by sleep spindles and K-complexes, 3) Stage 3 by delta waves, and 4) Stage 4 by predominantly delta waves. As we progress through the stages, brain activity slows down, with deeper stages associated with slower wave patterns.
During sleep, different brain waves are produced depending on the sleep stage. For example, during REM (rapid eye movement) sleep, the brain exhibits beta and theta waves, while in non-REM sleep stages, delta waves are prominent. Delta waves are associated with deep sleep and are typically seen in stages 3 and 4 of non-REM sleep.
There is alpha or stage one sleep, theta or stage two sleep, delta or statge 3 sleep, and alpha with REM (stage 4 sleep).
Delta sleep is the first sleep to be made up after sleep has been lost. Stage 4 sleep.
Slow wave sleep occurs after Stage 1 and Stage 2 sleep, and prior to REM sleep. There is more slow wave sleep present toward the beginning of the night, while more REM sleep is present toward the end of the night's sleep. In slow wave sleep, delta waves are present on the EEG (Electroencephalogram), which measures brain activity. These waves are long and slow, as opposed to the sharp waves of Stage 2 sleep. It is ecause of the shape of these waves that the stage is called slow wave sleep.
You return to stage 3, then stage 2 (delta sleep) before going to REM sleep (stage 5).
You return to stage 3, then stage 2 (delta sleep) before going to REM sleep (stage 5).