title: Circadian and wake-dependent influences on subjective sleepiness, cognitive throughput, and reaction time performance in older and young adults.
abstract: OBJECTIVE
  To assess circadian and homeostatic influences on subjective sleepiness and cognitive performance in older adults when sleep and waking are scheduled at different times of day; to assess changes in subjective sleepiness and cognitive performance across several weeks of an inpatient study; and to compare these findings with results from younger adults.
  
  
  METHODS
  Three 24-h baseline days consisting of 16 h of wakefulness and an 8-h sleep opportunity followed by 3-beat cycles of a 20-h forced desynchrony (FD) condition; 18 20-h "days," each consisting of 13.33 h of scheduled wakefulness and 6.67 h of scheduled sleep opportunity.
  
  
  METHODS
  Intensive Physiological Monitoring Unit of the Brigham and Women's Hospital General Clinical Research Center.
  
  
  METHODS
  10 healthy older adults (age 64.00 +/- 5.98 y, 5 females) and 10 healthy younger adults (age 24.50 +/- 3.54 y, 5 females).
  
  
  METHODS
  Wake episodes during FD scheduled to begin 4 h earlier each day allowing for data collection at a full range of circadian phases.
  
  
  RESULTS
  Subjective sleepiness, cognitive throughput, and psychomotor vigilance assessed every 2 h throughout the study. Core body temperature (CBT) data collected throughout to assess circadian phase. Older subjects were less sleepy and performed significantly better on reaction time (RT) measures than younger subjects. Decrements among younger subjects increased in magnitude further into the experiment, while the performance of older subjects remained stable.
  
  
  CONCLUSIONS
  Our findings demonstrate that the waking performance and alertness of healthy older subjects are less impacted by the cumulative effects of repeated exposure to adverse circadian phase than that of young adults. This suggests that there are age-related changes in the circadian promotion of alertness, in the wake-dependent decline of alertness, and/or in how these 2 regulatory systems interact in healthy aging.
authors.affiliation: Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. esilva@rics.bwh.harvard.edu
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Silva
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Ronda
authors.forename: James K
authors.initials: JK
authors.lastname: Wyatt
authors.forename: Jeanne F
authors.initials: JF
authors.lastname: Duffy
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D001143:Arousal; D001831:Body Temperature; D002940:Circadian Rhythm; D003071:Cognition; D003072:Cognition Disorders / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D011930:Reaction Time; D020178:Sleep Disorders, Circadian Rhythm / Q000150:complications / Q000503:physiopathology; D012893:Sleep Wake Disorders / Q000150:complications* / Q000503:physiopathology; D014851:Wakefulness; D055815:Young Adult
references.citation: Neurobiol Aging. 1986 Mar-Apr;7(2):97-100
references.pmid: 3960269
references.citation: J Am Geriatr Soc. 2009 Jul;57(7):1245-51
references.pmid: 19460089
references.citation: Behav Neurosci. 2008 Aug;122(4):928-35
references.pmid: 18729646
references.citation: Neurobiol Aging. 2005 Oct;26(9):1307-19
references.pmid: 16182904
references.citation: Am J Physiol. 1999 Oct;277(4 Pt 2):R1152-63
references.pmid: 10516257
references.citation: Psychol Sci. 2003 Nov;14(6):549-57
references.pmid: 14629685
references.citation: J Consult Psychol. 1948 Jan-Feb;12(1):20-31
references.pmid: 18905836
references.citation: Neurobiol Aging. 1982 Winter;3(4):299-309
references.pmid: 7170047
references.citation: Psychophysiology. 2001 Mar;38(2):232-42
references.pmid: 11347869
references.citation: J Clin Endocrinol Metab. 1982 Jul;55(1):27-9
references.pmid: 7200489
references.citation: Physiol Behav. 1986;37(6):915-8
references.pmid: 3786485
references.citation: J Physiol. 1999 Apr 15;516 ( Pt 2):611-27
references.pmid: 10087357
references.citation: Chronobiol Int. 1990;7(2):143-53
references.pmid: 2242508
references.citation: Science. 1999 Jun 25;284(5423):2177-81
references.pmid: 10381883
references.citation: Biol Cybern. 1994;71(2):115-21
references.pmid: 8068773
references.citation: Experientia. 1983 Jun 15;39(6):551-8
references.pmid: 6343111
references.citation: J Psychiatr Res. 1975 Nov;12(3):189-98
references.pmid: 1202204
references.citation: J Cogn Neurosci. 2006 Apr;18(4):508-21
references.pmid: 16768357
references.citation: Am J Physiol. 1998 Nov;275(5 Pt 2):R1478-87
references.pmid: 9791064
references.citation: Sleep. 1994 Apr;17(3):236-41
references.pmid: 7939123
references.citation: Chronobiol Int. 1996 Nov;13(5):373-86
references.pmid: 8957588
references.citation: J Psychosom Res. 2004 May;56(5):497-502
references.pmid: 15172205
references.citation: Electroencephalogr Clin Neurophysiol. 1986 May;63(5):414-25
references.pmid: 2420557
references.citation: Aviat Space Environ Med. 1976 Mar;47(3):221-30
references.pmid: 769776
references.citation: Sleep. 1986 Jun;9(2):353-64
references.pmid: 3505735
references.citation: Neurobiol Aging. 1989 Jan-Feb;10(1):21-5
references.pmid: 2755554
references.citation: Behav Brain Res. 2006 Apr 3;168(2):312-7
references.pmid: 16386807
references.citation: Lancet. 1992 Oct 17;340(8825):933-6
references.pmid: 1357348
references.citation: Biometrics. 1982 Dec;38(4):963-74
references.pmid: 7168798
references.citation: Ann Med. 1999 Apr;31(2):130-40
references.pmid: 10344586
references.citation: Psychol Bull. 1978 Nov;85(6):1256-74
references.pmid: 734012
references.citation: Arch Ital Biol. 2001 Apr;139(3):253-67
references.pmid: 11330205
references.citation: J Sleep Res. 1992 Mar;1(1):24-9
references.pmid: 10607021
references.citation: J Psychiatr Res. 1982-1983;17(1):37-49
references.pmid: 7183759
references.citation: Sleep. 1997 Apr;20(4):294-300
references.pmid: 9231956
references.citation: J Sleep Res. 2006 Dec;15(4):376-85
references.pmid: 17118094
references.citation: Sleep. 1991 Dec;14(6):540-5
references.pmid: 1798888
references.citation: J Clin Endocrinol Metab. 1988 Mar;66(3):648-52
references.pmid: 3350912
references.citation: Sleep. 2004 May 1;27(3):374-81
references.pmid: 15164887
references.citation: Sleep. 2001 Aug 1;24(5):565-77
references.pmid: 11480654
references.citation: Sleep. 2006 Jan;29(1):55-7
references.pmid: 16453981
references.citation: Sleep. 2006 May;29(5):609-18
references.pmid: 16774150