Table 1.

Mean Prestudy Reported Times in Bed

	Baseline		Night shift schedule
	Time in bed	Time out of bed	Time in bed	Time out of bed
T01	23:25	7:30	9:30	17:28
T02	22:01	6:04	8:05	16:05
T04	00:00	8:01	10:02	18:06
T05	23:26	7:29	9:29	17:36
T06	23:58	8:08	–	–

Mean times in and out of bed reported in sleep/wake logs for each participant. During the baseline (pre-study) period, subjects maintained a habitual day-oriented sleep/wake schedule prior to their admission to the laboratory. Each maintained an 8-hr sleep/darkness period that was based on their reported habitual bed and wake times. During the ambulatory phase of the investigation (experimental days 6-10), participants continued to maintain the night-oriented schedule by remaining awake at night and sleeping during the day while at home. Subject T06 did not participate in the last segment of the investigation (experimental days 6-12).