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.