ultradian rhythms

• ultradian rhythms

  a type of biological rhythm with a frequency of more than one cycle in 24 hours - stages of sleep
• example of ultradian rhythm

  • stages of sleep / the sleep cycle
• stages of sleep:

  5 distinct stages of sleep that span approximately 90 minutes - a cycle that continues throughout the course of the night

  each of theses stages is characterised by a different level of brainwave activity which can be monitored using an EEG
• stages of sleep: stages 1 and 2

  • light sleep where a person may be easily woken
  • stage 1 -> brain waves are high frequency and have a short amplitude (alpha waves)
  • stage 2 -> the alpha waves continue but there are occasional random changes in pattern called sleep spindles

  
• stages of sleep: stage 3 and 4

  • this is known as deep sleep or slow wave sleep
  • the brain waves are delta waves with lower frequency and higher amplitude
  • difficult to wake someone at this point

  
• what type of wave does each stage produce?

  stage 1 = alpha waves

  stage 2 = alpha waves and sleep spindles

  stage 3 and 4 = delta waves

  stage 5 = theta waves
• stages of sleep: stage 5 (REM sleep)

  • body is paralysed yet brain activity closely resembles that of the awake brain
  • brain produces theta waves and the eyes occasionally move around - rapid eye movement
  • dreams are most often experienced during REM sleep - but also deep sleep

  
• types of waves in the sleep cycle

  A) alpha waves

  B) alpha waves and sleep spindles

  C) Delta waves

  D) theta sleep

  E) rise and fall

  F) time between

  G) each peak

  H) frequency

  I) height

  J) electrical activity

  K) amplitude

  
• ultradian rhythms AO3 - improved understanding

  • improved understanding of age-related changes in sleep
  • sleep scientists have observed that slow wave sleep reduces with age
  • growth hormone is mostly produced during slow wave sleep therefore is reduced in older people
  • Cauter - the resulting sleep deficit may explain various issues in old age - reduced alertness
  • to increase slow wave sleep relaxation and medication may be used
  • practical value
• ultradian rhythms AO3 - individual differences

  • these is significant variation between people
  • Tucker - found large differences between ppts in terms of the duration of each sleep stage (stage 3 and 4 )
  • these differences are likely biologically determined
  • difficult to describe 'normal sleep' in any meaningful way