Stage 4. apex:)
Delta
Stage 4 sleep. Stage 3 also often emits delta waves.
Delta waves
Delta Waves (APEX)
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.
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).
You return to stage 3, then stage 2 (delta sleep) before going to REM sleep (stage 5).
3,4. Both stages are now combined and are just called stage 3, SWS ( slow wave sleep) or deep sleep. Stage 3 is the deepest stage.
Delta sleep is stage four of the deep sleep cycle. This is necessary to feel well rested. to increase the Delta waves during sleep, regular exercise is the only method. Of course, exercise has other benefits.
delta