Older people awaken more frequently but fall back asleep at the same rate as younger people.
OBJECTIVE
To determine whether the increased wake within a bedrest episode in healthy older people is due to an increased number and/or increased duration of awakenings by evaluating the rates of transition between sleep and wake bouts within a bedrest episode.


METHODS
Analysis of previously reported polysomnographic data from 13 older and 11 younger healthy individuals scheduled to sleep at many different phases of the endogenous circadian cycle during conditions of forced desynchrony (18.7 hours wake: 9.3 hours bedrest) of the circadian and wake-bedrest cycles.


METHODS
General clinical research center


METHODS
None.


METHODS
None.


RESULTS
Older subjects had an approximately 2.7-fold increased rate of awakening from sleep but the same rate of falling back asleep as younger subjects. These differences between young and older individuals were observed at most circadian phases and throughout the bedrest episodes. In addition, the circadian variation in transition rates was greater in younger than older subjects.


CONCLUSIONS
These results suggest that the reduced consolidation of sleep within a bedrest episode is due to difficulties remaining asleep, rather than falling asleep once awake, and is a primary change in sleep with aging.
Klerman
Elizabeth B
EB
Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. ebklerman@hms.harvard.edu
Davis
Joanna B
JB
Duffy
Jeanne F
JF
Dijk
Derk-Jan
DJ
Kronauer
Richard E
RE
D000368:Aged; D002940:Circadian Rhythm / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D017286:Polysomnography / Q000295:instrumentation*; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*