ultradian ryhty

• what are Ultraradian rhythms?

  Cycles that last less than 24 hours, such as the cycle of sleep stages that occur throughout the night
• • One example of ultradian rythyms are sleep cycles, this has 4 stages of NREM sleep followed by a stage of REM sleep, this cycle takes approximately 90 minutes and can repeat up to  5 times a night
• • 1-2 During these stages brainwave patterns become slower and more rhythmic, starting with alpha waves progress to theta waves. (muscle activity slows down)(heart rate breathing pattern decreases)
  • 3 and 4 are ‘deep sleep’ or slow wave sleep stages, where it is difficult to wake someone up. This stage is associated with slower delta waves. (rhythmic breathing and limited muscle activity)
  • Stage 5 REM (or dream) sleep. Here the body is paralysed (to stop the person acting out their dream) and brain activity resembles that of an awake person. ( heart rate increases)
• BRAC

  • A psychological arousal mechanism in humans, hypothezized to occur both in sleep and wakefulness.
  • characterised by different states of alertness to physiological fatigue/rest  every 90 minutes.
  • Kleitman suggested that mind could only concentrate for up to 90 minutes when the body runs out of resources which results in fatigue, lack of concentration and hunger
• • Differences have been observed in people which make investigating patterns difficult,
  • Tucker et al found significant differences between participants in terms of duration of each stage,particularly stages 3 and 4 .
  • THis demonstrates that there may be innate individual differences in ultradian rhythms
  • research into some people's sleep patters could lack populational validity
• • Studied in a controlled lab environment
  • removed extraneous variables,situational differences eg. children noises in household, temp,mattresses, - able to establish a causal relationship patterns couldnt be attributed to situational factors,support for the role of innate biological factors 
  • However, the way it is conducted ,may tell us little about ultradian rhythms in humans. When investigating sleep patterns participants may be subjected to a specific level of control and be attached to monitors.
  • Low ecological validity- not a valid representation about how they would usually sleep
• • research support for BRAC
  • Research support for the BRAC comes from studies of elite performers. Ericsson found that elite violinists generally practice for 90 minutes at a time and often nap between practice sessions. 
  • He found the same pattern among other musicians and athletes, chess players and writers.
  • This supports the existence of a 90 minute ultradian cycle of alertness and fatigue.
• • research into some people's sleep patters usually Studied people in a controlled lab environment ]
  • Positives -removed extraneous variables eg. children noises in household, temperature,mattresses, Situational differences can affect sleep - able to establish a causal relationship and ensure differences were biological and could not be attributed to situational factors,support for the role of innate biological factors 
  • However, the way it is conducted ,may still tell us little about ultradian rhythms in humans.When investigating sleep patterns participants may be subjected to a specific level of control and be attached to monitors.
  • This may be Low ecological validity as it is not a valid representation about how they would usually sleep
• • Differences have been observed in people which make investigating patterns difficult,
  • Tucker et al found significant differences between participants in terms of duration of each stage,particularly stages 3 and 4 .
  • THis demonstrates that there may be innate individual differences in ultradian rhythms, meaning that it is worth focusing on these differences during investigations into sleep cycles.
  • furthermore Gardener remained awake for 264 hours. After this experience, he slept for just 15 hours and over several nights he recovered 70% of stage 4 sleep, 50% of his REM sleep and very little of his other stages. This highlights the flexibility in terms of the different stages within the sleep cycle and the variable nature of this ultradian rhythm.
• Research support for brac comes from studies of elite performers,ericsson found that elite violinists

  Research support for the BRAC comes from studies of elite performers. Ericsson found that elite violinists generally practice for 90 minutes at a time and often nap between practice sessions. 

  He found the same pattern among other musicians and athletes, chess players and writers.

  This supports the existence of a 90 minute ultradian cycle of alertness and fatigue.

  usefull applications- knowledge can help athetes or professionals to optimise their full potential