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Circadian regulation of human sleep and age-related changes in its timing, consolidation and EEG characteristicsThe light-entrainable circadian pacemaker located in the suprachiasmatic nucleus of the hypothalamus regulates the timing and consolidation of sleep by generating a paradoxical rhythm of sleep propensity; the circadian drive for wakefulness peaks at the end of the day spent awake, ie close to the onset of melatonin secretion at 21.00-22.00 h and the circadian drive for sleep crests shortly before habitual waking-up time. With advancing age, ie after early adulthood, sleep consolidation declines, and time of awakening and the rhythms of body temperature, plasma melatonin and cortisol shift to an earlier clock hour. The variability of the phase relationship between the sleep-wake cycle and circadian rhythms increases, and in old age sleep is more susceptible to internal arousing stimuli associated with circadian misalignment. The propensity to awaken from sleep advances relative to the body temperature nadir in older people, a change that is opposite to the phase delay of awakening relative to internal circadian rhythms associated with morningness in young people. Age-related changes do not appear to be associated with a shortening of the circadian period or a reduction of the circadian drive for wake maintenance. These changes may be related to changes in the sleep process itself, such as reductions in slow-wave sleep and sleep spindles as well as a reduced strength of the circadian signal promoting sleep in the early morning hours. Putative mediators and modulators of circadian sleep regulation are discussed.
Document ID
20040141946
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Dijk, D. J.
(Brigham and Women's Hospital and Harvard Medical School Boston, MA 02115, United States)
Duffy, J. F.
Date Acquired
August 22, 2013
Publication Date
April 1, 1999
Publication Information
Publication: Annals of medicine
Volume: 31
Issue: 2
ISSN: 0785-3890
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: AG06072
CONTRACT_GRANT: AG09975
CONTRACT_GRANT: RR02635
Distribution Limits
Public
Copyright
Other
Keywords
Review, Tutorial
Review
NASA Discipline Regulatory Physiology
Non-NASA Center

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