What is the deepest stage of sleep?

In the deepest level of sleep, stage IV sleep, the predominant EEG activity consists of low frequency (1–4 Hz), high-amplitude fluctuations called delta waves, the characteristic slow waves for which this phase of sleep is named. The entire sequence from drowsiness to deep stage IV sleep usually takes about an hour.

What are the 5 stages of sleep?

Stages of Sleep

  • Stage 1 of non-REM sleep. When you first fall asleep, you enter stage 1 of non-REM sleep. …
  • Stage 2 of non-REM sleep. This is the stage where you are actually fully asleep and not aware of your surroundings. …
  • Stage 3 of non-REM sleep. …
  • Stage 4 of non-REM sleep. …
  • Stage 5: REM sleep.

What are the 4 stages of sleep in order?

Frequently Asked Questions

  • NREM stage 1: Less than 10 minutes, begins right after falling asleep.
  • NREM stage 2: Lasts anywhere from 30 to 60 minutes.
  • NREM stage 3: Lasts between 20 to 40 minutes14.
  • REM sleep: About 10 minutes for the first period during sleep, then increasingly longer with later periods15.

What is sleep stage 4 called?

These four sleep stages are called non-rapid eye movement (non-REM) sleep, and its most prominent feature is the slow-wave (stage IV) sleep. It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep.