FIGURE 1.

Inpatient study schedules. Study day is indicated along the left side and representative clock hour along the top. Solid black bars represent scheduled sleep episodes in 0 lux. Dark gray, light gray, and white indicate parts of the study conducted under 1 lux, 4 lux, and 90 lux lighting levels, respectively. Gray bars with black outlines indicate times during wake episodes where participants maintained a semi-recumbent posture in bed. The timing of standardized breakfast meal responses (solid colored bars; purple, red, and green used for chronic sleep restriction (CSR), CSR&RCD, and Control groups, respectively), for assessment of glucose and insulin and euglycemic-hyperinsulinemic clamps (diagonal hatched bars; purple and green used for CSR and Control groups, respectively) is also indicated. The standardized meal response on day 9 is available only in 4 CSR and 4 Control participants.