Sleep stages

• Sleep stages - First sleep stages

  Sleep onset:

  Alpha and theta waves

  Light sleep, easily woken

  Sudden twitching
• Sleep stages - Second sleep stage

  Late night stage:

  Mainly theta waves

  Eye movements stop

  Temp and heart rate drop
• Sleep stages - Third sleep stage

  Deep sleep (1):

  Mainly delta + some faster waves

  Between a light and deep sleep
• Sleep stages - Fourth sleep stage

  Deep sleep (2):

  Almost all delta waves

  Sleep walking and night terrors most likely

  Very hard to wake
• Sleep stages - REM

  Rapid eye movement sleep:

  When dreams occur

  Fluttering eyelids

  Muscle paralysis