Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

The dim light melatonin onset following fixed and free sleep schedules.

Authors
Burgess-HJ; Eastman-CI
Source
J Sleep Res 2005 Sep; 14(3):229-237
NIOSHTIC No.
20028723
Abstract
The time at which the dim light melatonin onset (DLMO) occurs can be used to ensure the correct timing of light and/or melatonin administration in order to produce desired circadian phase shifts. Sometimes however, measuring the DLMO is not feasible. Here we determined if the DLMO was best estimated from fixed sleep times (based on habitual sleep times) or free (ad libitum) sleep times. Young healthy sleepers on fixed (n=60) or free (n=60) sleep schedules slept at home for 6 days. Sleep times were recorded with sleep logs verified with wrist actigraphy. Half-hourly saliva samples were then collected during a dim light phase assessment and were later assayed to determine the DLMO. We found that the DLMO was more highly correlated with sleep times in the free sleepers than in the fixed sleepers (DLMO versus wake time, r=0.70 and r=0.44, both P<0.05). The regression equation between wake time and the DLMO in the free sleepers predicted the DLMO in an independent sample of free sleepers (n=23) to within 1.5 h of the actual DLMO in 96% of cases. These results indicate that the DLMO can be readily estimated in people whose sleep times are minimally affected by work, class and family commitments. Further work is necessary to determine if the DLMO can be accurately estimated in people with greater work and family responsibilities that affect their sleep times, perhaps by using weekend wake times, and if this method will apply to the elderly and patients with circadian rhythm disorders.
Keywords
Sleep-disorders; Sleep-deprivation; Lighting; Lighting-systems; Sampling; Sampling-methods; Circadian-rhythms
Contact
Helen J. Burgess, Biological Rhythms Research Laboratory, Rush University Medical Center, 1645 W. Jackson Blvd, Suite 425, Chicago, IL 60612, USA
CODEN
JSRSEU
Publication Date
20050901
Document Type
Journal Article
Email Address
helen_j_burgess@rush.edu
Funding Amount
846000
Funding Type
Grant
Fiscal Year
2005
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003954
Issue of Publication
3
ISSN
0962-1105
Priority Area
Work Environment and Workforce: Organization of Work
Source Name
Journal of Sleep Research
State
IL
Performing Organization
Rush University Medical Center, Chicago, Illinois
TOP