THE EFFECTS OF REGULARIZING SLEEP-WAKE SCHEDULES ON DAYTIME SLEEPINESS

The present study evaluated the differential effects of two manipulati ons of sleep-wake schedules on daily subjective ratings of daytime sle epiness of college undergraduate students. Two experimental conditions were compared: a sleep only group and a regularity group. Subjects in both conditions were given a lower limit for total sleep time (7.5 ho urs). Subjects in the regularity group received an additional instruct ion to keep a regular sleep schedule. The study was longitudinal and p rospective. Following a baseline period (12 days), the experimental co nditions were introduced. The experimental phase lasted 4 weeks and ov erall compliance was good. A follow-up phase (1 week) began 5 weeks pa st termination of the experimental phase. The findings indicated that when nocturnal sleep is not deprived, regularization of sleep-wake sch edules is associated with reduced reported sleepiness. Subjects in the regular schedule condition reported greater and longer lasting improv ements in alertness compared with subjects in the sleep only condition and reported improved sleep efficiency.