Effects of rapid versus slow accumulation of eight hours of sleep loss

The present study assessed alertness, memory, and performance following three schedules of similar to8 hr of sleep loss (slow, intermediate, and rapid accumulation) in comparison to an 8-hr time in bed (TIB) sleep schedule. Twelve healthy individuals aged 21-35 completed each of four conditions according to a Latin Square design: no sleep loss (8-hr TIB for 4 nights; 2300-0700), slow (6-hr TIB for 4 nights; 0100-0700), intermediate (4-hr TIB for 2 nights; 0300-0700), and rapid (0-hr TIB for 1 night) sleep loss. On each day, participants completed a multiple sleep latency test (MSLT), a probed-recall memory task, a psychomotor vigilance task, a divided attention task, and the Profile of Mood States. Rapid sleep loss produced significantly more impairment on tests of alertness, memory, and performance compared to the slow accumulation of a comparable amount of sleep loss. The impairing effects of sleep loss vary as a function of rate, suggesting the presence of a compensatory adaptive mechanism operating in conjunction with the accumulation of a sleep debt.