Biological Approach: Ultradian Rhythm Flashcards
What are Ultradian Rhythms
A cycle repeated throughout 24 hour circadian day.
Stage 1 of sleep
Relatively light stage of sleep, and is considered to be a transition period between wakefulness and sleep. Slow brain waves in this stage. Lasts around 5-10 minutes.
Stage 2 of sleep cycle
Lasts around 20 minutes and the brain begins to produce bursts of rapid, rhythmic brain wave activity known as sleep spindles. Body temp and heart rate decrease.
Stage 3 of sleep cycle
Deep, slow brain waves known as delta waves begin to emerge during stage 3 sleep, transition period between light sleep and very deep sleep.
Stage 4 of sleep cycle
Slow brain waves known as delta waves. Lasts around 30 minutes.
REM - stage 5 of sleep cycle
Dreaming occurs during REM sleep and is characterised by the rapid and random movement of the eyes as well as increased respiration rate and increased brain activity. We have around 3-5 REM episodes a night. Dreaming occurs because of increased brain activity but voluntary muscles become paralysed. About 20-25% of sleep is REM.