Sleep

Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness.

thumb|upright=1.5|In this illustration, politician Daniel O'Connell dreams of a confrontation between his outfit and that of [[George IV (r. 1820–1830; shown via a thought bubble)]]

thumb|325px|Bedroom on the Detmold Open-air Museum premises

A yawn is a reflex in vertebrate animals characterized by a long inspiratory phase with gradual mouth gaping, followed by a brief climax (or acme) with muscle stretching, and a rapid expiratory phase with muscle relaxation, which typically lasts a few seconds. For fish and birds, this is described as gradual mouth gaping, staying open for at least three seconds and subsequently a rapid closure of the mouth. Almost all vertebrate animals, including mammals, birds, reptiles, amphibians, and even fish, experience yawning. The study of yawning is called chasmology.

thumb|A bedroom in Germany thumb|Bedroom in the Indian Mound Cottage at Jekyll Island A bedroom or bedchamber is a room situated within a residential or accommodation unit, primarily used for sleeping. A typical Western bedroom contains as bedroom furniture one or two beds, a clothes closet, and bedside table and dressing table, both of which usually contain drawers. In dwellings with multiple stories, bedrooms are often on the upper floors. Beds range from a crib for an infant; a single or twin bed for a toddler, child, teenager or single adult; to bigger sizes like a full, double, queen, kin

thumb| Northern bat hibernating in [[Norway]] thumb|Bats hibernating in a silver mine

spontaneous sleep orgasm

type of clock used to wake up a sleeping person at a certain time

thumb|right|upright=1.25|A painting of a young woman taking a siesta. (The Hammock, [[Gustave Courbet (1844))]] thumb|upright=1.1|People taking a siesta in a haystack, Lendava, Yugoslavia, 1957 A siesta (from Spanish, pronounced and meaning "nap") is a short nap taken in the early afternoon, often after the midday meal. Such a period of sleep is a common tradition in some countries, particularly those in warm-weather zones. The "siesta" can refer to the nap itself, or more generally to a period of the day, generally between 2 and 5p.m. This period is used for sleep, as well as leisure, midday

natural internal process that regulates the sleep-wake cycle

thumb|right|Owl|Owls are well known for being nocturnal, but some owls are active during the day.

Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep, the condition of being in a drowsy state due to circadian rhythm disorders, or a symptom of other health problems. It can be accompanied by lethargy, weakness and lack of mental agility.

pseudoscience - the attempt to predict various aspects of a person's life through simple mathematical cycles; not to be confused with scientific term "biological rhythm"

world day

spontaneous erection during or after sleep

any sleep pattern with multiple periods of sleep in a 24-hour period

thumb|Teenage girls at a sleepover, Gainesville, Georgia, 1952 A sleepover, also known as a slumber party or pajama party, is a social occasion in which a young person stays at the home of a friend. Multiple people and/or friends may sleepover at the friend's home. Typically a younger person will partake in a sleepover; however, an adult or older person may sleep at a friend's home.

a person who tends to stay up until late at night

state of consciousness between waking and sleeping induced by a guided meditation

thumb|Example of an EEG alpha wave thumb|Example of an EEG theta wave

thumb|A man napping in a hammock, on a [[patio in Costa Rica]]

telling of a story to somebody about to sleep

set of practices around healthy sleeping

condition of abnormally deep sleep or a stupor from which it is difficult to rouse

sleep in non-human beings

Sleep-learning or sleep-teaching (also known as hypnopædia or hypnopedia) is an attempt to convey information to a sleeping person, typically by playing a sound recording to them while they sleep. Although sleep is considered an important period for memory consolidation, scientific research has concluded that sleep-learning is not possible. Once a concept explored in the early history of psychology, sleep-learning appears frequently in fiction and parapsychology, and is widely considered to be pseudoscience.

225px|thumb|right|Astronauts Richard H. Truly and [[Guion Bluford sleeping on board the Challenger. Bluford, in the foreground (upside-down) wears a sleep mask. Astronauts may find it difficult to sleep in space, especially if they are light sensitive.]] 225px|thumb|right|Sleep mask

EEG waveform that occurs during sleep

short sleep

f.lux (pronounced "flux") is a cross-platform computer program that adjusts a display's color temperature according to location and time of day, offering functional respite for the eyes. The program is designed to reduce eye strain during night-time use, helping to reduce disruption of sleep patterns.

2023 video game developed by Select Button and Niantic

A chronotype is the behavioral manifestation of an underlying circadian rhythm's myriad physical processes. A person's chronotype is the propensity for the individual to sleep at a particular time during a 24-hour period. Eveningness (delayed sleep period; most active and alert in the evening) and morningness (advanced sleep period; most active and alert in the morning) are the two extremes with most individuals having some flexibility in the timing of their sleep period. However, across development there are changes in the propensity of the sleep period with pre-pubescent children preferring

__NOTOC__

spontaneous swelling of the clitoris during sleep or when waking up

person who usually gets up early in the morning and goes to bed early in the evening

Co-sleeping or bed sharing is a practice in which babies and young children sleep close to one or both parents, as opposed to in a separate room. Co-sleeping individuals sleep in sensory proximity to one another, where the individual senses the presence of others. This sensory proximity can either be triggered by touch, smell, taste, or noise. Therefore, the individuals can be a few centimeters away or on the other side of the room and still have an effect on the other. It is standard practice in many parts of the world, and is practiced by a significant minority in countries where cribs are a

mental exercise to fall asleep

falling asleep while working

Diagnostic tool used to diagnose sleep disorders

Bedding company

time of day when the devil, demons or ghosts are supposed to come out

Actigraphy is a non-invasive method of monitoring human rest/activity cycles. A small actigraph unit, also called an actimetry sensor, is worn for a week or more to measure gross motor activity. The unit is usually in a wristwatch-like package worn on the wrist. The movements the actigraph unit undergoes are continually recorded and some units also measure light exposure. The data can be later read to a computer and analysed offline; in some brands of sensors the data are transmitted and analysed in real time.

thumb|Child Asleep (The Rosebud) by Thomas Sully (1841)

drowsiness just after waking up

2019 studio album by Moby

study of the neuroscientific and physiological basis of the nature of sleep

self-care trend of spending large amounts of time in bed

behaviour or productivity method consisting in waking up early in the morning

data sheet

application that adjusts the computer display's color temperature

book by Matthew Walker

special types of structures or chairs that allow people to nap, often shielded

medical condition

Beddit Oy (formerly Finsor Oy) is a Finnish technology company that sells sleep tracking devices and a sleep tracking application to help monitor sleep. The company was founded in October 2006 and released their first sleep tracker in November 2013. In May 2017, Beddit was acquired by Apple Inc.

process of quantitatively measuring a person's sleep

quantitative measure of the tendency to fall asleep

traditional social custom and courting behavior

device that produces white noise or other similar random sounds

test that records body activity during sleep