Age-related changes in the time course of vigilant attention during 40 hours without sleep in men

Study Objectives: To examine whether vigilant attention and sleepiness develop differently during prolonged wakefulness in young and older men. Design, Setting, and Participants: Psychomotor vigilance task (PVT) performance and subjective sleepiness were determined in 14 sessions at 3 hour intervals in healthy young (n = 12, mean age: 25.2 years, range: 21-31 years) and older (n = 11, mean age: 66.4 years, range: 61-70 years) men who were kept awake for 40 hours under continuous supervision in a sleep laboratory and on the morning after the recovery night. Measurements and Results: PVT speed, response lapses and performance variability, and subjective sleepiness were analyzed. Sleep deprivation led to reversal of an age-related difference in PVT speed at the circadian trough of performance on the morning of the second day of prolonged wakefulness (Session x Age interaction: P < .0006). Beginning after 22 hours of wakefulness, the young men also produced more lapses (P < .004), showed higher performance instability (P < .0001), and felt sleepier (P < .03) than older men, especially during the morning after the night without sleep. Conclusions: Vigilant attention is more impaired after 1 night without sleep in young men than in older men, which has important implications for the prevention of accidents associated with the loss of sleep.