Ultradian Rhythms

• What are ultradian rhythms?

  Biological processes that repeats more frequency than once a day
• Example of an ultradian rhythm?

  Stages of sleep
• How long do the stages of sleep usually take to complete?

  90 minutes
• Stages 1 and 2 of sleep represent the ‘sleep escalator’ where participant can easily be awoken
• Stages 3 and 4 coincide with deeper and slower delta waves
• Stage 5 is represented with REM sleep
• What does REM stand for?

  Rapid eye movement
• What is REM sleep closely associated with?

  Dreaming and characterised by movement inhibition and a sensory blockage
• How many sleep cycles do humans usually go through in one night?

  4 to 5 times
• The overall pattern of sleep stages in consistent however there are some individual differences with newborn babies spending 80 % of sleep in REM compared to 20 to 25 % in adults. Suggests the stages of sleep are not a simple process but adapt to the developmental needs of the individual
• Technology and devices based on understanding of sleep stages have been developed. These track sleep and help individuals improve sleep. Avoid waking in stage 4 stops people feeling groggy and disoriented. This technology leads to happier, healthier and more economically productive population
• What waves are in stages 1 and 2?

  Alpha
• What waves are in stages 3 and 4?

  Delta
• What is a strength of research into ultradian rhythms?

  Improved understanding of age related changes in sleep
• Sleep scientists have observed that slow wave sleep (SWS) reduces with age. Growth hormone is mostly produced during SWS therefore is reduced in older people. Therefore, the resulting sleep deficits may explain various issues in old age such as reduced alertness. In order to increase SWS, relaxation and medication may be sued (Practical value)
• Limitation: Significant variation between people in terms of duration of each sleep state, particularly stages 3 and 4. Differenes likely to be biologically determined