Ultradian rhythm - stages of sleep

• Brainwaves


  Distinctive patterns that can be observed by an electroencephalogram while you sleep
• Brainwave patterns


  1. Pass through a series of patterns

  2. Repeat around every 90 minutes
• Circadian rhythm


  24-hour sleep/wake cycle
• Infradian rhythm


  Menstrual cycle, less frequent than every day
• Ultradian rhythm


  More frequent than every day
• Brainwave frequency


  Number of waves per second
• Brainwave amplitude


  Size of the wave
• Main brainwave patterns


  • Delta
  • Theta
  • Alpha
  • Beta
  • Gamma
• Stages of sleep


  1. N1

  2. N2

  3. N3

  4. REM
• Non-REM sleep


  N1, N2, N3
• REM sleep


  Rapid eye movement sleep, stage in which you dream
• Sleep cycle


  1. N1 to N3

  2. Repeat 4-5 times per night
• N1 sleep


  Sensation of moving from awake to asleep, easy to wake, body can move suddenly, hypnic jerks, hypnagogic hallucinations
• N2 sleep


  Deeper sleep, less easy to wake, body relaxes, heart rate and body temperature falls, eyes still
• N3 sleep


  Deep sleep, heart rate and body temperature falls, eyes still, slow wave sleep
• REM sleep


  Brain active, body paralyzed, associated with dreaming
• Intense physical activity by ultra marathon runners


  Longer sleep and increased proportion of slow-wave sleep
• REM sleep


  Role in memory consolidation
• REM sleep


  Brain recovery
• Newborn babies


  About 80% of night's sleep in REM, compared to 20-25% in adults
• Stages 3 and 4 sleep combined into N3 stage
• Circadian and ultradian rhythms


  Connected, perhaps shouldn't be seen as separate processes
• Longest period of REM sleep

  Coincides with lowest point in circadian body temperature cycle
• Nocturnal penile tumescence


  Erection during night and morning, coincides with REM sleep
• Nocturnal penile tumescence helps maintain penile health by providing fresh oxygenated blood