Ultradian rhythms

• Occurs more than once every 24 hours
• Stages of sleep is an example

  • Free running, maintains cycle for about 90 minutes
  • Can be influenced by exogenous zeitgebers like noises
  • 4 stages
• Stages:

  1. 4-5%, light sleep
  2. 45-55%, breathing pattern & heart rate slows
  3. 4-6% deep sleep begins, brain begins to generate slow delta waves
  4. 12-55% very deep sleep, brain produces delta waves
  5. 20-25% REM (rapid eye movement), brainwaves speed and dreaming occurs