Ultradian rhythms

Question 1

What is an ultradian rhythm?

Answer 1

Type of biological rhythm with a frequency of more than one cycle in 24 hours

Question 2

How can the 5 stages of sleep be studied?

Answer 2

Monitored using an EEG
Different levels of brainwave activity

Question 3

What is stages 1 and 2?

Answer 3

Light sleep
Person easily woken
Stage 1 - high frequency, short amplitude
(Alpha waves)
Stage 2 - alpha waves continue but there are occasional random changes in patter called sleep spindles

Question 4

What are stages 3 and 4?

Answer 4

Deep sleep or slow wave sleep
Delta waves
Lower frequency and higher amplitude
Difficult to wake someone up at this point

Question 5

What is stage 5?

Answer 5

REM sleep
Body paralysed yet brain activity closely resembles that of an awake brain
Brain produced theta waves
Eyes occasionally move around
Rapid Eye Movement
Dreams are most often experiences in REM sleep but may also occur in deep sleep

Question 6

How long do the stages of sleep span for?

Answer 6

Approximately 90 mins

Question 7

What is a strength of ultradian rhythms?

Answer 7

Improved understanding of age related changes in sleep
Sleep scientists observed slow wave sleep reduced with age
Growth hormone is mostly produced during SWS therefore is reduced in older people
Cauter et al - resulting sleep deficit may explain various old age issues
In order to increase SWS relaxation and medication may be used
Suggesting knowledge of ultradian rhythms has practical value

Question 8

What is a negative of ultradian rhythms?

Answer 8

Significant variation between people
Tucker et al
Large differences between participants in terms of duration of each sleep stage
Particularly stage 3 - 4
Suggested these differences are likely to be biologically determined
Making it difficult to describe ‘normal sleep’ in a meaningful way