NREM sleep


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Related to NREM sleep: Stages of Sleep

NREM sleep

(ĕn′rĕm′)

sleep

(slep)
A periodic state of rest accompanied by varying degrees of unconsciousness and relative inactivity. Although sleep is thought of as something that occurs once each 24-hr day, at least half of the world's population has an afternoon nap or siesta as part of their lifelong sleep-wake pattern. The need for and value of sleep is obvious; yet there is no explanation of why it provides a daily renewal of a feeling of health and well-being.

The sleep-wake cycle varies in relation to the age and gender of the individual. The newborn may sleep as much as 20 hr each day; a child, 8–14 hr, depending on age; adults, 3–12 hr with a mean of 7–8 hr, which may decrease to 6.5 hr in the elderly. Women over 35 tend to sleep more than men. There is great individual variation in the amount and depth of sleep.

Sleep has two states: non–rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. NREM sleep and REM sleep alternate during the night; each cycle requires 90–100 min. NREM sleep makes up approx. 75% of the sleep cycle, and REM sleep approx. 25%, with individual variations.

People deprived of sleep for several days or more become irritable, fatigued, unable to concentrate, and usually disoriented. Performance of mental and physical tasks deteriorates. Some people experience paranoid thoughts and auditory, visual, and tactile illusions or hallucinations. Deprivation of REM sleep may cause anxiety, overeating, and hypersexuality. The effects of sleep deprivation are reversed when the normal sleep-wake cycle is resumed. See: non–rapid eye movement sleep; rapid eye movement sleep

Physiological Changes during Sleep

The following physiological changes occur during sleep: body temperature falls; secretion of urine decreases; heart rate and respiration become slower and more regular during NREM sleep and then more rapid and less regular during REM sleep. During REM sleep, blood flow to the brain is increased; breathing is more irregular; heart rate and blood pressure vary; cerebral blood flow and metabolic rate increase; and penile erections may occur. There is an increased secretion of growth hormone during the first 2 hr of sleep; surges of adrenocorticotropic hormone (ACTH) and cortisol secretion occur in the last half of the sleep period. Luteinizing hormone secretion is increased during sleep in pubescent boys and girls, and prolactin secretion is increased in men and women, esp. immediately after the onset of sleep.

In evaluating sleep, it is important to know that hand waving, arm swinging, laughing, and flatus occur during normal sleep. Snoring may be clinically insignificant but, when accompanied by apnea, can be harmful.

dreaming sleep

Rapid eye movement sleep.

desynchronized sleep

Rapid eye movement sleep.

hypnotic sleep

1. Sleep induced by hypnotic suggestion.
2. Sleep induced by the use of medicines classified as hypnotics.

CAUTION!

Many hypnotic drugs are habit-forming.

light sleep

A colloquial term for the first stage of non–rapid eye movement (NREM) sleep. It is sometimes also applied to the second stage of NREM sleep.

non–rapid eye movement sleep

Abbreviation: NREM sleep
Sleep during which non–rapid eye movements occur. Dreams do not occur in NREM sleep. It has four stages: in stage 1, the transition from wakefulness to sleep occurs; eye movements are slow, and an electroencephalogram (EEG) shows low brain wave activity. In stage 2, EEG activity is increased, and spikes called K complexes appear. In stage 3, eye movement ceases; wave frequency is reduced and amplitude increased. In stage 4, the EEG is dominated by large spikes (delta rhythm). Stages 3 and 4 are considered deep sleep. Synonym: synchronized sleep See: rapid eye movement sleep; sleep

pathological sleep

Excessive or disordered sleep.

paradoxical sleep

A term sometimes used as a synonym for rapid eye movement (REM) sleep. REM sleep is the preferred term.

rapid eye movement sleep

Abbreviation: REM sleep
Sleep during which rapid eye movements occur. Dreams occur in REM sleep. It follows stage 4 of non–rapid eye movement (NREM) sleep; electroencephalographic activity is similar to that of NREM stage 1; and muscle paralysis normally occurs. Synonym: desynchronized sleep; dreaming sleep See: non–rapid eye movement sleep; sleep

synchronized sleep

Non–rapid eye movement sleep.

non–rapid eye movement sleep

Abbreviation: NREM sleep
Sleep during which non–rapid eye movements occur. Dreams do not occur in NREM sleep. It has four stages: in stage 1, the transition from wakefulness to sleep occurs; eye movements are slow, and an electroencephalogram (EEG) shows low brain wave activity. In stage 2, EEG activity is increased, and spikes called K complexes appear. In stage 3, eye movement ceases; wave frequency is reduced and amplitude increased. In stage 4, the EEG is dominated by large spikes (delta rhythm). Stages 3 and 4 are considered deep sleep. Synonym: synchronized sleep See: rapid eye movement sleep; sleep
See also: sleep

Non-rapid eye movement (NREM) sleep

A type of sleep that differs from rapid eye movement (REM) sleep. The four stages of NREM sleep account for 75-80% of total sleeping time.
Mentioned in: Sleep Disorders
References in periodicals archive ?
Muscle tone in the upper airway decreases slightly in NREM sleep and decreases markedly and disappears in REM sleep, resulting in an increase in upper airway resistance.
During the tonic periods, which account for the majority of REM sleep, muscle tone is decreased and the EEG is similar to that seen during stage 1 NREM sleep.
EEG delta activity during NREM sleep was studied as slow wave activity during NREM sleep is an indicator of sleep quality (Tokunaga et al.
Administration of testosterone to healthy pre-menopausal women for 12 days elevates the apnoeic threshold closer to eupnoea, narrowing the magnitude of hypocapnic required for induction of central apnoea during NREM sleep (47).
Slow-wave sleep (SWS): A collective term for stages 3 and 4 of NREM sleep.
Tricyclic antidepressants suppress REM sleep activity and increase NREM sleep.
Each epoch was assigned to one of the following categories: wakefulness (low-amplitude EEG activity, high-voltage EMG activity), SWS (large-amplitude, synchronous EEG with sleep spindles present, greatly diminished tonic EMG, eyes closed, small eye movement potentials present, recumbent posture, usually lying on the animal's side or curled up with head down), REM sleep (desynchronized EEG, absence of tonic EMG, intermittent REM potentials, occasional body twitches while maintaining a recumbent sleep posture), NREM sleep (high-amplitude slow or spindle EEG activity, low-amplitude EMG activities), light sleep (equals NREM sleep minus SWS).
Effect of lung inflation on pulmonary resistance during NREM sleep.
Clinically, knowing not only the quality but also the quantity of both REM and NREM sleep is critical in our understanding of the severity of our patient's sleep disorders and clinical studies that do not include this information may under serve our patients.
SDB in those with CKD disrupts the normal NREM sleep, attenuates the vagal modulation of heart rate, with a predominance of the sympathetic nervous system.
The presence of NREM sleep instability was studied with calculation of the cyclic alternating pattern (CAP) rate.
Radioactive glucose isotopes were delivered intravenously when brain waves and other physiological signs indicated the onset of REM sleep -- during which much dreaming occurs -- and NREM sleep.