Publication Date:
1999-06-26
Description:
Regulation 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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Czeisler, C A -- 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 -- MO1-RR02635/RR/NCRR NIH HHS/ -- P01-AG09975/AG/NIA NIH HHS/ -- R01-GM53559/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1999 Jun 25;284(5423):2177-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Circadian, Neuroendocrine, and Sleep Disorders Section, Division of Endocrinology, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10381883" target="_blank"〉PubMed〈/a〉
Keywords:
Adult
;
Aged
;
Aging/*physiology
;
Biological Clocks/genetics/*physiology
;
Body Temperature
;
Circadian Rhythm/genetics/*physiology
;
Darkness
;
Female
;
Humans
;
Hydrocortisone/blood
;
Light
;
Male
;
Melatonin/blood
;
Middle Aged
;
Sleep
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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