Figure 1.

Experimental protocol. (A; n = 8) condition order A. (B; n = 8) condition order B. Underlines represent scheduled wakefulness and colored boxes represent scheduled sleep. A recovery sleep opportunity (black box) was provided on study day 14 prior to discharge from the laboratory for participants in condition order A. Time of day is plotted as relative clock hour with scheduled waketime arbitrarily assigned to 08:00 am for the baseline and 9H conditions. All other times and protocol events are referenced to this arbitrarily assigned value (e.g. blood draws occurring 1 hours after scheduled waketime during the baseline condition are reported as occurring at 09:00 am). Actual sleep timing and protocol events were based on habitual sleep schedules of each individual participant, thus all participants were studied at their habitual sleep and circadian phase for baseline. Blood collection for untargeted metabolomics occurred on study days 3, 8, and 13, represented by T1, T5, T9, and T13 (note that T17 and T21 blood collections are not represented on the figure as they were not used for biomarker analyses).