Student Area

Sleep Stages

Awake

When you are awake and alert, your brainwaves are very fast (dark and close together). [Click for picture.] These are called beta waves.

Drowsy Awake

When you are drowsy with your eyes closed, your brainwaves look very different. They are a little more spread apart, and they look like zig-zag stripes. [Click for picture.] These are called alpha waves.

Stage 1 Sleep

In Stage 1 sleep, your brainwaves get shorter, and they spread out a little more. [Click for picture.] These are called theta waves. If we woke you up in Stage 1 sleep, you would probably say you hadn’t quite fallen asleep yet.... it is a very light kind of sleep. If we watched your eyes in Stage 1 sleep, they might appear to be rolling slowly around, under your eyelids.

Stage 2 Sleep

In Stage 2 sleep, some taller brainwaves start to appear once in a while. Special waves begin to appear, called K-complexes and sleep spindles (neither ever appears in Stage 1). [Click for picture.] If we woke you up from Stage 2, you would probably agree that you had been sleeping.

Slow Wave Sleep (SWS)

In Slow Wave Sleep, your brainwaves slow down and get much bigger and wider. [Click for picture.] These are called delta waves. It might be very hard to wake you up from this kind of sleep! It is the deepest sleep of the night. Your mind is "out cold", but your body is free to move around. People may sleepwalk during Slow Wave Sleep.

REM SLEEP

In Rapid Eye Movement (REM) sleep, your brainwaves are small and fast again, a lot like in Stage 1. [Click for picture.] Your eyes make sharp movements under your eyelids, but the rest of your body cannot move -- it is paralyzed. This is a good thing, because dreams often happen in REM sleep... and if your body started acting out all your dreams, you might get hurt (or maybe even arrested!)

Click here to see how we go through these sleep stages over the course of a typical night’s sleep.