| Light exposure patterns in healthy older and young adults. | |
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MedLine Citation:
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PMID: 20348462 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Aging is associated with an earlier timing of circadian rhythms and a shorter phase angle between wake time and the timing of melatonin secretion or the core body temperature nadir. Light has a phase-dependent effect on the circadian pacemaker, and modifications of habitual light exposure in older people could contribute to a change in the timing of circadian rhythms or in the phase angle of entrainment. In this study, we compare natural light exposure of community-dwelling older and young subjects studied at the same time of year, focusing on the pattern of light exposure across the waking day. We recorded light exposure data for 3 to 8 days from 22 older (aged 66.01 +/- 5.83) and 22 young subjects (aged 23.41 +/- 4.57), living at home on self-selected sleepwake schedules, and matched for time of year. All subjects were from New England (latitude 42.3 degrees N to 43 degrees N). We compared the percentage of the waking day spent by older and young subjects at 4 different light levels (from very dim to very bright). We compared hourly averaged light exposure data in each group according to clock time and with respect to each subject's daily sleepwake times. Although both age groups spent more than half of their waking hours in dim or moderate room light intensity (<100 lux), we found that the older subjects spent a significantly greater percentage of their waking day in the brighter light levels (> or =1000 lux); their hourly averaged light exposure levels were also significantly greater whether we examined the data with respect to absolute clock time, to wake time, or to bed time, and this was true across all seasons. We found that healthy older people were exposed to significantly higher levels of light throughout their waking day than young people. Differences in natural light exposure may contribute to the age-related phase advance of the circadian pacemaker and its later timing relative to the sleepwake cycle. This hypothesis should be explored further in carefully designed prospective studies. |
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Authors:
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Karine Scheuermaier; Alison M Laffan; Jeanne F Duffy |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of biological rhythms Volume: 25 ISSN: 1552-4531 ISO Abbreviation: J. Biol. Rhythms Publication Date: 2010 Apr |
Date Detail:
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Created Date: 2010-03-29 Completed Date: 2010-06-21 Revised Date: 2011-07-27 |
Medline Journal Info:
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Nlm Unique ID: 8700115 Medline TA: J Biol Rhythms Country: United States |
Other Details:
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Languages: eng Pagination: 113-22 Citation Subset: IM |
Affiliation:
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Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. kscheuermaier@rics.bwh.harvard.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Age Factors Aged Aging* Biological Clocks Circadian Rhythm Female Humans Light* Lighting Male Middle Aged Sleep Time Factors Wakefulness |
| Grant Support | |
ID/Acronym/Agency:
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AG06072/AG/NIA NIH HHS; AG09975/AG/NIA NIH HHS; AG18578/AG/NIA NIH HHS; AT002129/AT/NCCAM NIH HHS; F32 AG031690-02/AG/NIA NIH HHS; F32 AG03910/AG/NIA NIH HHS; HL77453/HL/NHLBI NIH HHS; M01 RR002635-130150/RR/NCRR NIH HHS; M01 RR002635-140429/RR/NCRR NIH HHS; MH45130/MH/NIMH NIH HHS; NS41886/NS/NINDS NIH HHS; P01 AG009975-14/AG/NIA NIH HHS; R01 AG006072-20/AG/NIA NIH HHS; R01 AT002129-02/AT/NCCAM NIH HHS; R01 HL077453-05/HL/NHLBI NIH HHS; R01 MH045130-19/MH/NIMH NIH HHS; R01 NS041886-04/NS/NINDS NIH HHS; R03 AG018578-01/AG/NIA NIH HHS; RR02635/RR/NCRR NIH HHS; T32 HL 07901/HL/NHLBI NIH HHS; T32 HL007901-12/HL/NHLBI NIH HHS |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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