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Sleep freely to know your DLMO



Details

  • Personal Author:
  • Description:
    We analyzed baseline sleep times from 120 young healthy subjects to determine the phase relationship between the DLMO and sleep in subjects following fixed or free sleep schedules. "Free sleepers" (N=60) slept at times of their own choosing and "fixed sleepers" (N=60) slept on a fixed schedule similar to their weekday schedule. Subjects completed sleep logs that were verified by actigraphy. We averaged sleep times from 6 days before we measured the DLMO (threshold=mean+2SD of first 3 low daytime points). The fixed sleepers had earlier DLMOs and sleep times (fixed: DLMO 20:46+/-1.1 h, bedtime (lights out) 23:17+/-0.9 h, wake time (lights on) 7:06+/-1.0 h; free: DLMO 22:41+/-1.5 h, bedtime 00:56+/-1.1 h, wake time 9:25+/-1.3 h, all p<0.001). There was no difference in the DLMO to bedtime interval (fixed: 2.5+/-1.1 h; free: 2.3+/-1.2 h), but the wake time to DLMO interval was slightly longer in the fixed sleepers (fixed: 13.7+/-1.1 h, free: 13.3+/-1.1 h, p=0.056). The highest correlation between sleep times and the DLMO was with wake time. Surprisingly, the correlation between wake time and the DLMO was higher in the free sleepers (free: r=0.70; fixed: r=0.44, p<0.05). This is likely because fixed sleepers slept at times determined by social factors, whereas free sleepers slept at times promoted by the circadian clock. Thus maintaining a fixed sleep schedule does not necessarily improve estimations of the timing of the DLMO. [Description provided by NIOSH]
  • Subjects:
  • Keywords:
  • Publisher:
    Society for Research on Biological Rhythms
  • Document Type:
    Text
  • Funding:
    Grant
  • Genre:
    Abstract or Summary
  • Place as Subject:
  • CIO:
    National Institute for Occupational Safety and Health (NIOSH)
  • Topic:
    Workplace Safety & Health
  • Location:
    North America
  • Pages in Document:
    44-45
  • NIOSHTIC Number:
    nn:20045634
  • Citation:
    Proceedings of the 9th meeting of the Society for Research on Biological Rhythms, June 23-26, 2004, Whistler, British Columbia. Urbana, IL: Society for Research on Biological Rhythms, 2004 Jun; :44-45
  • Federal Fiscal Year:
    2004
  • Performing Organization:
    Rush University Medical Center, Chicago, Illinois
  • Peer Reviewed:
    False
  • Start Date:
    19990930
  • Source Full Name:
    Proceedings of the 9th meeting of the Society for Research on Biological Rhythms, June 23-26, 2004, Whistler, British Columbia
  • End Date:
    20090430
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:0aa711f2468c08d5302c8c5edf60997d064e5de43d4ebd1eef3f3b6b6db2d57203cc54905ff4105e0a8d568ecf794efd76aebc82b5364b53c1042ed9414a29c8
  • Download URL:
  • File Type:
    Filetype[PDF - 72.44 KB ]
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