Sleep and Awake Behavior during Gradual Sleep Reduction

Two young adults, 1 male and 1 female, reduced their total sleep time by 30 min. every 2 wk. from an initial 7.5 hr. to 4 hr. The 4-hr. regimen was maintained for 3 wk. and then ad lib. sleep was permitted. A third S withdrew from the study at the 4.5-hr. period. Daily sleep and nap logs reflected the difficulty in maintaining the restricted sleep schedule after the 6-hr. period. EEG sleep records indicated earlier onset of REM sleep at 5.5 hr. but there were no changes in other measures. At 4 hr., a marked increase in stages 3 and 4 was present with a decrease in REM and stage 2 sleep. Mood and performance measures showed changes beginning at the 5.5-hr. sleep regimen. Follow-up reports indicate both Ss have maintained a sleep schedule 1 to 2 hr. below their baselines.