Circadian rhythm
the physical, mental, and behavioral changes an organism experiences over a 24-hour cycle
Dreams
Dreams are stories and images that our minds create while we sleep.
Electroencephalograph (EEG)
a recording of brain activity.
Hypersomnia
excessive sleepiness
Insomnia
a common sleep disorder. With insomnia, you may have trouble falling asleep, staying asleep, or getting good quality sleep.
Melatonin
a hormone in your body that plays a role in sleep.
Napping
a short period of sleep, typically taken during daytime hours as an adjunct to the usual nocturnal sleep period.
Narcolepsy
a chronic neurological disorder that affects the brain's ability to control sleep-wake cycles.
Night Terrors
a sleep disorder in which a person quickly awakens from sleep in a terrified state.
Nightmares
a disturbing dream associated with negative feelings, such as anxiety or fear that awakens you.
Parasomnia
occur in a state that lies between sleep and wakefulness.
Restless Legs Syndrome
A condition characterized by a nearly irresistible urge to move the legs, typically in the evenings.
Sleep
Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited.
Sleep apnea
a potentially serious sleep disorder in which breathing repeatedly stops and starts.
Sleep deprivation
occurs when an individual fails to get the amount of sleep that they need.
Sleep paralysis
a temporary inability to move or speak that occurs directly after falling asleep or waking up.
Sleep study
diagnose sleep disorders.
Snoring
the hoarse or harsh sound that occurs when air flows past relaxed tissues in your throat, causing the tissues to vibrate as you breathe.
Stage 1 (Non-REM) sleep
heartbeat, eye movements, brain waves, and breathing activity begin to taper down
Stage 2 (Non-REM) sleep
is still light sleep, but deeper than stage 1.
Stage 3 (Non-REM) sleep
Deep sleep
Stage 4 (REM Sleep)
an even deeper sleep where the brain waves further slow and sleepers are very difficult to wake.
Somnambulism
Sleep walking
Wakefulness
a condition of being alert, rather than sleepy.