Chronic sleep curtailment, even without extended (>16-h) wakefulness, degrades human vigilance performance.
Millions of individuals routinely remain awake for more than 18 h daily, which causes performance decrements. It is unknown if these functional impairments are the result of that extended wakefulness or from the associated shortened sleep durations. We therefore examined changes in objective reaction time performance and subjective alertness in a 32-d inpatient protocol in which participants were scheduled to wakefulness durations below 16 h while on a 20-h "day," with randomization into standard sleep:wake ratio (1:2) or chronic sleep restriction (CSR) ratio (1:3.3) conditions. This protocol allowed determination of the contribution of sleep deficiency independent of extended wakefulness, since individual episodes of wakefulness in the CSR condition were only 15.33 h in duration (less than the usual 16 h of wakefulness in a 24-h day) and sleep episodes were 4.67 h in duration each cycle. We found that chronic short sleep duration, even without extended wakefulness, doubled neurobehavioral reaction time performance and increased lapses of attention fivefold, yet did not uniformly decrease self-reported alertness. Further, these impairments in neurobehavioral performance were worsened during the circadian night and were not recovered during the circadian day, indicating that the deleterious effect from the homeostatic buildup of CSR is expressed even during the circadian promotion of daytime arousal. These findings reveal a fundamental aspect of human biology: Chronic insufficient sleep duration equivalent to 5.6 h of sleep opportunity per 24 h impairs neurobehavioral performance and self-assessment of alertness, even without extended wakefulness.
['McHill|Andrew W|AW|', 'Hull|Joseph T|JT|', 'Wang|Wei|W|', 'Czeisler|Charles A|CA|', 'Klerman|Elizabeth B|EB|']
D000328:Adult D001143:Arousal D001288:Attention D002940:Circadian Rhythm D003071:Cognition D005260:Female D064368:Healthy Volunteers D006801:Humans D008297:Male D017286:Polysomnography D011597:Psychomotor Performance D011930:Reaction Time D057566:Self Report D012890:Sleep D012892:Sleep Deprivation D012893:Sleep Wake Disorders D013997:Time Factors D014851:Wakefulness
alertness circadian insufficient sleep forced desynchrony sleepiness