1. Ultradian Rhythm STAGES OF SLEEP: Link to Spec 4.2.2

2. What are Ultradian Rhythms?
Biological rhythms with more than one cycle in 24 hours. (P)
Within a night’s sleep, we move systematically through different phases of sleep, taking approximately 90 minutes. (E)
Therefore a single sleep cycle is an Ultradium rhythm. (E)

3. Why do we sleep? What is sleep? What function does it serve?
How much sleep is enough?
Why do we dream?
What qualifies good / bad sleep?

4. EEG MACHINE Berger 1930s

5. Wave Glossary
Frequency (hz)
Amplitude

6. AWAKE
EEG shows HIGH FREQUENCY and LOW AMPLITUDE waves known as ALPHA and BETA waves (less than 12 hz) ALERT

7. STAGE 1
ALPHA and BETA waves decrease, THETA waves begin which are lower frequency, greater amplitude (4-8 hz) RELAXED, EASY TO WAKE Lasts about 15 mins

8. STAGE 2
Mainly THETA waves, some SLEEP SPINDLES (increased frequency) and K COMPLEXES (increased amplitude) 8-15 hz LIGHT SLEEP Lasts about 20 mins

9. STAGE 3
THETA waves continue, DELTA waves begin – lower frequency, greater amplitude. 2-4 hz DEEP SLEEP, SOME DREAMING Lasts about 15 mins

10. STAGE 4
Mainly DELTA waves hz VERY DEEP SLEEP DIFFICULT TO WAKE UP SLEEPWALKING Lasts about 30 mins

11. REM SLEEP
BETA waves return, similar to relaxed AWAKE state 12 hz+ VIVID DREAMING (Kleitman 1957) TEMPORARY MUSCLE PARALYSIS PARADOXICAL SLEEP. Lasts about mins

12. Up and down the “sleep escalator”
1, 2, 3, 4, 3, 2, REM
2, 3, 4, REM
2, REM
10, 10, 40, 60 (how long the REM cycles are)