FIGURE 1.

Schematic showing representative inpatient study schedule. Black bars indicate scheduled sleep opportunities, while white boxes indicate days that blood samples were drawn. All participants first underwent three sleep extension days with 16‐hr TIB and three baseline days with either 8‐ or 10‐hr TIB before beginning a 2–3 week FD segment. During FD, participants lived on 28‐hr “days” with 11.67 hr or 6.5 hr sleep opportunities. Fasting blood samples were drawn within 40 min of wake time during the first week, second week, or both first and third weeks of FD