Biological Rhythms: Ultradian Rhythms

Question 1

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What is an ultradian rhythm?

Answer 1

• These are rhythms which occur more frequently than 24 hours
  e.g. sleep

Question 2

What are sleep cycles & how long do they last?

Answer 2

• Each sleep cycle lasts around 90 minuets
• Each sleep cycle consists of 5 stages of sleep
• Each sleep cycle is different

Question 3

What is stage 1 & 2 of the sleep cycle?

Answer 3

• At beginning of sleep/ light sleep
• Brainwave patterns are slow & your muscles relax with your heartbeat,breathing & eye movements slow

Question 4

What is stage 3&4 of the sleep cycle?

Answer 4

• Known as deep sleep or slow wave sleep
• The brain waves are delta waves with lower frequency & higher amplitude
• Difficult to wake someone up at this point

Question 5

What is stage 5 of the sleep cycle?

Answer 5

REM sleep
* The body is paralysed yet brain activity closely resembles that of the awake brain
* During this time the brain produces theta waves & the eyes occasioanly move around- Thus rapid eye movement
* Dreams are often experienced during REM sleep

Question 6

Whats one strength of research into ultradium rhythms?

Answer 6

• It has improved understanding of age related changes in sleep
• Sleep scientists have observed that slow wave sleep reduced with age
• Growth hormone is usually produced during SWS so becomes deficient in older people

Kauter et al (200) found resulting sleep deficit may explain various impariments in old age e.g. reduced alertness
In order to increase SWS- relaxation medication may be used
Suggests that knwlege of ultradium rhythms has practical value

Question 7

What is one limitation of ultradian rhythms?

Answer 7

• There is a significant variation between people
• Tucker et al found larger differences between ppts in terms of the duration of each sleep stage, particulalry stages 3 &4
• Suggested that these differences are biologically determined
• Makes it difficult to describe normal sleep in any meaningful way