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Studies on ultradian rhythmicity in human sleep and associated neuroendocrine rhythms.

Weitzman ED; Fukushima D; Nogeire C; Hellman L; Sassin J; Perlow M; Gallagher TF
Chronobiology 1974 Jan; :503-505
Evidence collected over the past 15 years suggests that the central nervous system of all mammals alternates between two distinct states of physiologic activity. This alternating sleep pattern has been called the short term REM/non REM sleep cycle. In a series of studies it was determined that during the latter half of the nocturnal sleep period, cortisol was secreted in an episodic manner. Under a defined and stable sleep/wake 24 hour cycle, normal young adult subjects had an average of nine secretory episodes with the subjects spending an average of 24 percent of the time in active secretion. No evidence was found for a basal level or steady state of cortisol concentration. Changes in cortisol output appeared to be due to differences in frequency and duration of secretory episodes and not to major changes in secretory rate. In a study of the effect of a prolonged 3 hour sleep/wake cycle on a group of seven subjects, a partial ultradian sleep/wake cycle was established. However, a prominent superimposed circadian sleep/wake cycle persisted through the entire 10 day study. Measurement of body temperature also demonstrated a persistence of the circadian rhythm throughout the 10 day 3 hour sleep/wake period with a partial shift, delay of about 4 to 6 hours. In the 3 hour cycle, cortisol output and secretory time were maximal for the first hour after awakening, were less for the second hour of awakening, and were minimal for the third hour. Analysis of the human growth hormone (GH) in five subjects during the ultradian period revealed that GH was released in 19 of 28 periods of sleep. An additional 17 episodes of hormonal release were not associated with sleep. Several were clearly associated with venipuncture or other stressful events.
NIOSH-Grant; Grants-other; Circadian-rhythms; Hormone-activity; Hormones; Sleep-deprivation; Nervous-system-function
Division of Neurology Montefiore Hosp and Med Center Division of Neurology Bronx, N Y 10467
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Other Occupational Concerns; Grants-other
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Montefiore Hospital and Medical Center, New York, New York
Page last reviewed: February 18, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division