infradian and ultradian rhyhms

• ultradian rhythms are biological rhythms that repeat more than once every 24 hours

  e.g the rest activity cycle and the sleep cycle
• the sleep cycle has 5 stages and lasts 90 minutes

  1. just starting to fall asleep and can be easily woken up
  2. body temperature and heart rate decrease
  3. blood pressure drops
  4. brain activity drops
  5. REM sleep. eyes move rapidly and brain is very active. this is where dreams occur

  
• infradian rhythms are biological rhythms that repeat less than once every 24 hours

  e.g the menstrual cycle is a 28 day cycle