Circadian rhythm

your body's natural, internal 24-hour clock that cycles physical, mental, and behavioral changes, primarily regulating the sleep-wake cycle, but also influencing hormones (like melatonin & cortisol), body temperature, and metabolism, guided mainly by light and dark cues from the environment.

Dreams

a series of thoughts, images, and sensations occurring in a person's mind during sleep.

EEG

a test that records the brain's electrical activity using electrodes placed on the scalp

Hypersomnia

a sleep disorder characterized by excessive daytime sleepiness and a persistent need to sleep, even after a full night's rest.

Insomnia

habitual sleeplessness; inability to sleep.

Melatonin

Melatonin is a hormone produced by the brain's pineal gland that regulates your sleep-wake cycle (circadian rhythm), signaling the body it's time to sleep as darkness falls and decreasing production with light.

Napping

sleep lightly or briefly, especially during the day.

Narcolepsy

is a chronic neurological disorder causing the brain to struggle with regulating sleep-wake cycles, which results in uncontrollable daytime sleepiness and sudden, irresistible urges to sleep.

Night Terrors

episodes of screaming, thrashing, and panic that happen during deep non-REM sleep.

Nightmares

a frightening or unpleasant dream.

Parasomnia

a sleep disorder characterized by abnormal, unpleasant motor, verbal, or behavioral events that occur during sleep or sleep transitions.

Restless Legs Syndrome

Restless Legs Syndrome (RLS), also called Willis-Ekbom Disease, is a neurological disorder causing an irresistible urge to move your legs, often with unpleasant sensations like crawling, tingling, or aching, especially when resting, which is temporarily relieved by movement like walking or stretching and typically worsens at night.

Sleep

a condition of body and mind that typically recurs for several hours every night, in which the eyes are closed, the postural muscles relaxed, the activity of the brain altered, and consciousness of the surroundings practically suspended.

Sleep apnea

a sleeping disorder in which the temporary cessation of breathing occurs more often than normal during sleep, and can cause hypoxemia and sleep deprivation.

Sleep deprivation

deprived of sleep

Sleep paralysis

a temporary inability to move or speak when falling asleep or waking up,

Sleep study

painless overnight test that monitors your body's functions while you sleep to diagnose sleep disorders like sleep apnea or insomnia, recording brain waves, heart rate, breathing, oxygen levels, and eye/leg movements to understand your sleep patterns and identify disruptions.

Snoring

the sound produced when air flow through the nose or mouth is obstructed, causing soft tissues at the back of the throat to vibrate.

Stage 1 (Non-REM) sleep

the lightest, transitional phase between wakefulness and sleep,

Stage 2 (Non-REM) sleep

a light stage of sleep where your heart rate and breathing slow further, body temperature drops, and eye movements stop, preparing you for deeper sleep.

Stage 3 (Non-REM) sleep

NREM 3 is the deepest stage of sleep, also known as slow-wave sleep,

Stage 4 (REM Sleep)

the final and most active stage of the sleep cycle.

Somnambulism

Somnambulism, or sleepwalking, is a parasomnia (sleep disorder) where a person performs complex activities like walking, talking, or even driving while still asleep, usually during deep non-REM sleep, often with little or no memory of the event

Wakefulness

a state of being alert, conscious, and responsive to the external world, characterized by brain activity that allows for perception, thought, and interaction, acting as the opposite of sleep where sensory input is mostly blocked.