Banking sleep: realization of benefits during subsequent sleep restriction and recovery.
OBJECTIVE
Determine whether sleep extension (a) improves alertness and performance during subsequent sleep restriction and (b) impacts the rate at which alertness and performance are restored by post-restriction recovery sleep.


METHODS
Participants were randomly assigned to an Extended (10 h time in bed [TIB]) or Habitual TIB [mean (SD) hours = 7.09 (0.7)] sleep group for one week, followed by 1 Baseline (10 hours or habitual TIB), 7 Sleep Restriction (3 h TIB), and 5 Recovery Sleep nights (8 h TIB). Performance and alertness tests were administered hourly between 08:00-18:00 during all in-laboratory phases of the study.


METHODS
Residential sleep/performance testing facility.


METHODS
Twenty-four healthy adults (ages 18-39) participated in the study.


METHODS
Extended vs. habitual sleep durations prior to sleep restriction.


RESULTS
Psychomotor vigilance task (PVT) lapses were more frequent and modified maintenance of wakefulness (MWT) sleep latency was shorter in the Habitual group than in the Extended group across the sleep restriction phase. During the Recovery phase, PVT speed rebounded faster (and PVT lapsing recovered significantly after the first night of recovery sleep) in the Extended group. No group differences in subjective sleepiness were evident during any phase of the study.


CONCLUSIONS
The extent to which sleep restriction impairs objectively measured alertness and performance, and the rate at which these impairments are subsequently reversed by recovery sleep, varies as a function of the amount of nightly sleep obtained prior to the sleep restriction period. This suggests that the physiological mechanism(s) underlying chronic sleep debt undergo long-term (days/weeks) accommodative/adaptive changes.
Rupp
Tracy L
TL
Division of Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA. tracy.rupp@amedd.army.mil
Wesensten
Nancy J
NJ
Bliese
Paul D
PD
Balkin
Thomas J
TJ
D000293:Adolescent; D000328:Adult; D001143:Arousal; D001288:Attention; D002940:Circadian Rhythm; D006970:Disorders of Excessive Somnolence / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D011597:Psychomotor Performance; D011930:Reaction Time; D012892:Sleep Deprivation / Q000523:psychology*; D014851:Wakefulness; D055815:Young Adult