Sleep and dreaming

• Sleep cycle


  A nightly pattern of deep sleep, light sleep and dreaming
• Non-REM sleep (NREM)


  • Non-rapid eye movement sleep where the person is not dreaming
  • Stage 1 (light sleep): easily woken up, muscles less active, eye movement slow and can suddenly twitch
  • Stage 2: brain waves slower, eye movements stop, bursts of brain activity (20 minutes)
  • Stage 3 (deep sleep): no eye movement, some faster brain waves, hard to wake up, children can experience night terrors or sleep walking
• REM sleep


  • Rapid eye movement sleep
  • Occurs for around 2 hours each night
  • Dreaming occurs
  • Rapid, shallow, irregular breathing
  • Muscle paralysis
• REM sleep


  Stimulates learning and is associated with an increase in proteins
• Benefits of sleep


  • Improved attention, focus and concentration
  • Enhanced immunity
  • Better memory and information processing
• Circadian rhythms


  Human body rhythms that have a daily (24 hour) cycle, e.g. sleep-wake cycle
• Ultradian rhythms


  Rhythms that occur in a period of less than 24 hours, e.g. sleep cycle