Stage 1
Takes 10-12 min; Light sleep; Breathing and heart rate is slow, body temp is low; Alpha/theta brain waves; Hypnic jerks
Stages 2, 3, and 4
Respiration rate, heart rate, muscle tension, and body temp all decline
Stage 2
10-25 min; High amplitude, slower frequency brain waves
Stages 3 and 4
Slow wave sleep- high amplitude, low frequency delta waves become prominent; Lasts about 30 min
Stage 5
EEG readings similar to when you're awake, vivid dreaming occurs (get progressively longer as you cycle through the stages and back to REM)