ultradian rhythms

• What is an ultradian rhythm?


  A biological rhythm that occurs many times during the day
• What is an example of an ultradian rhythm?


  Eating
• What is an example of ultradian rhythms?


  Stages of sleep - psychologists found that we experience 5 stages of sleep, each roughly 90 minutes long, and it can be categorised by different levels of brainwave activity
• What is stage 1 in the sleep cycle?


  • Drowsiness - eyes move very slowly and muscle activity decreases
• What is stage 2 in the sleep cycle?


  • Light sleep - eye movement stops, heart rate and breathing rate decrease
• What is stage 3 and 4 of the sleep cycle 


  • Deep sleep - no eye movements and no muscle activity
• What is stage 5 in the sleep cycle?


  • REM - Rapid Eye Movements, heart rate and breathing increase
  • Dreams occur during this stage so arms and legs muscles are paralysed to prevent you from acting out dreams
• What is the evidence supporting stages of sleep?


  • William Dement and Nathaniel Kleitman (1957) monitored sleep patterns of 9 adults pps in sleep lab
  • Brainwave activity was recorded on an EEG and controlled effects of caffeine and alcohol
  • REM was highly correlated with dreaming