BIOLOGICAL CLOCKS AND STAGES OF SLEEP: ch 5

circadian rhythm

an approximately 24 hour biological cycle shaped by internal clocks and environmental time cues

light exposure

timed bright light helps shift or synchronize the body clock; timing matters for jet lag

melatonin

a hormone involved in signaling biological night; timing affects its usefulness

N1

light transitional non-REM sleep

N2

non-REM sleep characterized by sleep spindles and K-complexes

N3

Deep slow-wave non-REM sleep; sleepwalking commonly occurs here

REM Sleep

often features vivid dreaming, substantial brain activity, rapid eye movements and reduced skeletal muscle tone; this combination is why it is called paradoxical sleep

how can bright light timed to the destination’s waking period help with jet lag

bright light acts as a powerful tool to help reset the biological clock in the thalamus