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Stability, precision, and near-24-hour period of the human circadian pacemakerRegulation of circadian period in humans was thought to differ from that of other species, with the period of the activity rhythm reported to range from 13 to 65 hours (median 25.2 hours) and the period of the body temperature rhythm reported to average 25 hours in adulthood, and to shorten with age. However, those observations were based on studies of humans exposed to light levels sufficient to confound circadian period estimation. Precise estimation of the periods of the endogenous circadian rhythms of melatonin, core body temperature, and cortisol in healthy young and older individuals living in carefully controlled lighting conditions has now revealed that the intrinsic period of the human circadian pacemaker averages 24.18 hours in both age groups, with a tight distribution consistent with other species. These findings have important implications for understanding the pathophysiology of disrupted sleep in older people.
Document ID
20040141918
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Czeisler, C. A.
(Harvard Medical School, Brigham and Women's Hospital 221 Longwood Avenue, Boston, MA 02115, United States)
Duffy, J. F.
Shanahan, T. L.
Brown, E. N.
Mitchell, J. F.
Rimmer, D. W.
Ronda, J. M.
Silva, E. J.
Allan, J. S.
Emens, J. S.
Dijk, D. J.
Kronauer, R. E.
Date Acquired
August 22, 2013
Publication Date
June 25, 1999
Publication Information
Publication: Science
Volume: 284
Issue: 5423
ISSN: 0036-8075
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: PO1-AG09975
CONTRACT_GRANT: MO1-RR02635
CONTRACT_GRANT: R01-GM53559
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Regulatory Physiology
Non-NASA Center

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