Figure 1

Within-subject, randomized, cross-over study design. Circadian alignment (A) and misalignment (B) protocols. For the former, scheduled sleep times were kept from 11PM to 7AM across all days, while for the latter these timings were inverted by 12 h after Baseline 2 (Day 3). T1-T4 corresponds to test days 1–4. During baseline days for both aligned and misaligned conditions, the Psychomotor Vigilance Task (PVT) and Probed Recall Memory (PRM) with Presentation phase (PP) and Recall phase (RP) were conducted at 2PM and 6PM, the Addition Task (ADD) at 12PM and 4PM, and the Unstable Tracking Task (TKT), Digit Symbol Substitution Task (DSST), Performance evaluation and effort scales (PEERS) and Karolinska Sleepiness Scale (KSS) at 12PM, 2PM, 4PM and 6PM. These timings were kept the same for the aligned protocol across all test days, while in the misaligned protocol they were inverted by 12 h for T1-T4.