A longitudinal assessment of sleep timing, circadian phase, and phase angle of entrainment across human adolescence.
The aim of this descriptive analysis was to examine sleep timing, circadian phase, and phase angle of entrainment across adolescence in a longitudinal study design. Ninety-four adolescents participated; 38 (21 boys) were 9-10 years ("younger cohort") and 56 (30 boys) were 15-16 years ("older cohort") at the baseline assessment. Participants completed a baseline and then follow-up assessments approximately every six months for 2.5 years. At each assessment, participants wore a wrist actigraph for at least one week at home to measure self-selected sleep timing before salivary dim light melatonin onset (DLMO) phase - a marker of the circadian timing system - was measured in the laboratory. Weekday and weekend sleep onset and offset and weekend-weekday differences were derived from actigraphy. Phase angles were the time durations from DLMO to weekday sleep onset and offset times. Each cohort showed later sleep onset (weekend and weekday), later weekend sleep offset, and later DLMO with age. Weekday sleep offset shifted earlier with age in the younger cohort and later in the older cohort after age 17. Weekend-weekday sleep offset differences increased with age in the younger cohort and decreased in the older cohort after age 17. DLMO to sleep offset phase angle narrowed with age in the younger cohort and became broader in the older cohort. The older cohort had a wider sleep onset phase angle compared to the younger cohort; however, an age-related phase angle increase was seen in the younger cohort only. Individual differences were seen in these developmental trajectories. This descriptive study indicated that circadian phase and self-selected sleep delayed across adolescence, though school-day sleep offset advanced until no longer in high school, whereupon offset was later. Phase angle changes are described as an interaction of developmental changes in sleep regulation interacting with psychosocial factors (e.g., bedtime autonomy).
Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL, United States of America.
Stephanie J
SJ
Crowley
E.P. Bradley Hospital Sleep Research Laboratory, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, United States of America.
Eliza
E
Van Reen
Sleep and Development Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States of America.
Monique K
MK
LeBourgeois
E.P. Bradley Hospital Sleep Research Laboratory, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, United States of America.
Christine
C
Acebo
E.P. Bradley Hospital Sleep Research Laboratory, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, United States of America; Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland; University Hospital of Child and Adolescent Psychiatry, University of Bern, Bern, Switzerland.
Leila
L
Tarokh
E.P. Bradley Hospital Sleep Research Laboratory, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, United States of America; The Bradley Hasbro Children's Research Center, Providence, RI, United States of America.
Ronald
R
Seifer
E.P. Bradley Hospital Sleep Research Laboratory, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, United States of America; The Bradley Hasbro Children's Research Center, Providence, RI, United States of America.
David H
DH
Barker
E.P. Bradley Hospital Sleep Research Laboratory, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, United States of America; Centre for Sleep Research, University of South Australia, Adelaide, Australia.
Mary A
MA
Carskadon
D056044:Actigraphy; D000293:Adolescent; D000375:Aging / Q000502:physiology; D002648:Child; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008550:Melatonin / Q000378:metabolism; D012463:Saliva / Q000378:metabolism; D012727:Sex Characteristics; D012890:Sleep / Q000502:physiology*; D013997:Time Factors
D008550:Melatonin