Figure 2.13 Sleep Stages and the Brain Waves Associated with Each Stage The various stages of sleep are indicated by changes in the brain waves in the EEG recordings. As you pass from awake to deep sleep (Stages 3 and 4), the brain waves get larger and slow down. After deep sleep, you ascend back through Stages 3 and 2 into REM sleep, for which the waves are more rapid and resemble those of Stage 1.