Sleep

Sleep

A naturally occurring and reversible altered state of consciousness, characterised by a reduction in awareness and responsiveness to external surroundings.

Circadian rhythm

Biological processes that coordinate the timing of body activities over a 24-hour period.

Ultradian rhythm

Biological processes that coordinate the timing of body activities over a period of less than 24 hours.

Melatonin

A hormone that induces drowsiness and decreases cell activity.

Zeitgeber

An environmental cue such as light, temperature and eating patterns that can synchronise and regulate the body’s circadian rhythm.

Altered state of consciousness

Any state that differs in awareness when compared to normal waking consciousness.

Consciousness

The awareness of your own internal mental processes, including your thoughts, feelings, sensations and perceptions, and your awareness of the external world around you.

Electroencephalography (EEG)

A measuring technique that detects, amplifies and records the electrical activity of the brain.

Electromyography (EMG)

A technique that detects, amplifies and records the electrical activity of the skeletal muscles.

Electro-oculography (EOG)

A measuring technique that detects, amplifies and records the electrical activity of the muscles controlling the eyes.

Naturally occurring altered state of consciousness

An altered state of consciousness that occurs without any external influence.

Non-rapid eye movement (NREM) sleep

A type of sleep characterised by a progressive decline in physiological activity.

Normal waking consciousness

A state associated with being aware of our internal and external environments.

Psychological construct

A concept that cannot be objectively observed or measured directly through the collection of data, but is widely understood to exist.

Rapid eye movement (REM) sleep

A type of sleep characterised by quick darting of the eyes behind closed eyelids and an increase in physiological activity.

Sleep diary

A subjective self-report tool used by a person to track their own sleep and wake patterns.

Video monitoring

A sleep study tool used to collect qualitative visual and audio information about a person’s sleep.

Suprachiasmatic nucleus

A region in the hypothalamus that regulates body activities to a daily schedule of sleep and wakefulness.

Partial sleep deprivation

Inadequate sleep either in quantity or quality.

Circadian rhythm sleep disorders

Disorders caused by changes to a person’s sleep-wake cycle.

Bright light therapy

The use of high-intensity light to treat circadian rhythm sleep disorders by shifting the timing of the sleep-wake cycle.

Sleep hygiene

Practices and habits that are conducive to sleeping well on a regular basis.