If you don't know it now then you're fucked

REM sleep: rapid eye movement; muscles paralysed; resembles waking state - short fast brain waves - brain active; vivid complex dreaming

Stage 3/4 of sleep: delta waves on EEG; deeply asleep; when sleepwalking occurs

Stage 2 of sleep: theta waves on EEG; K complexes (large brain wave) and sleep spindles (burst of faster activity)

Stage 1 of sleep: theta waves on EEG; lightly asleep

The sleep stages are an example of a ultradian rhythm as their cycle is less than 24 hours

During adulthood, % of REM sleep decreases to 25% and stage 4 disappears. Also sleep apnoea is more common.

Children - lark' chronotype - go to sleep and wake up early. Adolescents - 'owl' chronotype - go to sleep late and wake up late.

Decoursey destroyed SCN of chipmunks - altered circadian rhythm - more vulnerable to predation - animals evolved to adapt to zeitgebers

Jetlag induced on mice by altering light exposure made them have premature deaths! Shows negative consequences of jet lag

study found that doing shift work for 15+ years made you 3x more likely to develop heart disease. Shows negative consequences of shift work

Sweat from another women rubbed beneath the nose made their menstrual cycles converge. This suggest menstruation is effected by pheromones

Reinberg studied women in cave for 3months in dim light. Menstrual cycle shortened to 25.7 days. Suggests light effects the menstrual cycle

An Exogenous Zeitgeber is an external environmental factor such as light. It entrains our rhythm to a regular 24 hour cycle.

Ultradian rhythm: less than 24hrs Circadian rhythm: 24hrs Infradian rhythm: longer than 24hrs

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An Endogenous Pacemaker (EP) is a biological mechanism which is in a small area of the brain near the hypothalamus called the SCN

Michael Siffre: in a cave for 6months + isolated from external cues. His circadian rhythm altered to 24.5hrs.