What are Ultradian Rhythms?
Biological rhythms with a cycle length of less than 24 hours
What are 2 examples of Ultradian Rhythms?
- The Stages of Sleep
- The Basic Rest-Activity Cycle
How many Stages of Sleep are there?
5
How long does the Stages of Sleep cycle last?
About 90 minutes
How many Stages of Sleep cycles does the average person go through each night?
5
What characterises each of the Stages of Sleep?
Different levels of brainwave activity which can be monitored using an EEG
Describe Stages 1 & 2 of the Stages of Sleep
- Light sleep, where a person can be easily woken
- Brain waves are high frequency and have a short amplitude
- These are known as alpha waves
What occasionally happens in Stage 2 of the Stages of Sleep?
There are spontaneous changes in brainwave patterns known as ‘sleep spindles’
Describe Stages 3 & 4 of the Stages of Sleep
- Deep sleep, or slow-wave sleep, where its difficult to wake a person up
- Brain waves are a lower frequency and have a short amplitude
- These are known as delta waves
Describe Stage 5 of the Stages of Sleep
- Brain wave activity closely resembles that of an awake brain
- Brain waves are a lower frequency and have a high amplitude
- These are known as theta waves
What occasionally happen in Stage 5 of the Stages of Sleep?
Rapid Eye Movement (REM), which is when the eyes move around
In what stage are dreams most often experienced in the Stages of Sleep?
Stage 5
Describe the Basic Rest-Activity Cycle
A proposed cycle characterised by periods of alertness followed by periods of physiological fatigue that occurs whilst awake
How long does the Basic Rest-Activity Cycle last?
90 minutes, similarly to the Stages of Sleep cycle that occurs whilst asleep
Who proposed the Basic Rest-Activity Cycle?
Kleitman
What study supports the Basic Rest-Activity Cycle?
- K. Anders Ericsson et al, who observed a group of prestigious violinists
- He found that the best performers tended for practise for 90 minute sessions, with them having breaks in between each session in order to ‘recharge’
What evidence supports the Stages of Sleep?
EEG scans, which monitor brainwave activity
Why is the evidence supporting the Stages of Sleep considered high quality?
It is empirical and objective, utilising scientific methods and sometimes being concluded in specialised sleep labs
Why is research conducted into the Basic Rest-Activity Cycle not considered compelling? (3 Points)
- There is limited research
- There is a lack of objective, empirical evidence
- Research conducted focuses of small, niche samples and so may not be generalisable
What evidence complicates research into the Stages of Sleep cycle?
- Tucker et al found significant differences in the duration of each stage between participants, especially the duration of Stages 3 & 4
- This suggests that there are individual differences in terms of the Stages of Sleep
What has recent published research (2017) linked less REM or Stage 5 sleep to?
A greater risk of developing dementia
What is still unclear in terms of Ultradian Rhythms?
What the endogenous pacemakers and exogenous zeitgebers are, and the role they play
