Sleeping in the context of "Wakefulness"

Diurnality is a form of plant and animal behavior characterized by activity during daytime, with a period of sleeping or other inactivity at night. The common adjective used for daytime activity is "diurnal". The timing of activity by an animal depends on a variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year. Diurnality is a cycle of activity within a 24-hour period; cyclic activities called circadian rhythms are endogenous cycles not dependent on external cues or environmental factors except for a zeitgeber. Animals active during twilight are crepuscular, those active during the night are nocturnal and animals active at sporadic times during both night and day are cathemeral.

A couch, also known as a sofa, settee, chesterfield, or davenport, is a cushioned piece of furniture that can seat multiple people. It is commonly found in the form of a bench with upholstered armrests and is often fitted with springs and tailored cushion and pillows. Although a couch is used primarily for seating, it may be used for sleeping. In homes, couches are normally put in the family room, living room, den, or lounge. They are sometimes also found in non-residential settings such as hotels, lobbies of commercial offices, waiting rooms, and bars. Couches can also vary in size, color, and design.

Lying – also called recumbency, prostration, or decubitus in medicine (from Latin decumbo 'to lie down') – is a type of human position in which the body is more or less horizontal and supported along its length by the surface underneath. Lying is the most common position while being immobilized (e.g. in bedrest), while sleeping, or while being struck by injury or disease.

Iatromantis is a Greek word whose literal meaning is most simply rendered "physician-seer." The iatromantis, a form of Greek "shaman", is related to other semimythical figures such as Abaris, Aristeas, Epimenides, and Hermotimus.In the classical period, Aeschylus uses the word to refer to Apollo and to Asclepius, Apollo's son.

According to Peter Kingsley, iatromantis figures belonged to a wider Greek and Asian shamanic tradition with origins in Central Asia. A main ecstatic, meditative practice of these healer-prophets was incubation (ἐγκοίμησις, enkoimesis). More than just a medical technique, incubation reportedly allowed a human being to experience a fourth state of consciousness different from sleeping, dreaming, or ordinary waking: a state that Kingsley describes as “consciousness itself” and likens to the turiya or samādhi of the Indian yogic traditions. Kingsley identifies the Greek pre-Socratic philosopher Parmenides as an iatromantis. This identification has been described by Oxford academic Mitchell Miller as "fascinating" but also as "very difficult to assess as a truth claim".

Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Parasomnias are dissociated sleep states which are partial arousals during the transitions between wakefulness, NREM sleep, and REM sleep, and their combinations.