Figure 1. A schematic of the in-laboratory protocol.

The in-laboratory session consisted of an adaptation night (day 0) followed by a 24 h wake/sleep cycle and a 24 h wake/wake cycle. White sections indicate wake periods (100 lux, free to move); grey sections indicate wakefulness in a semi-recumbent position in dim light (<5 lux); black sections indicate sleep periods in a supine position in the dark (0 lux with eye masks). Standardized meals are represented by triangles; blue sections show the set urine collection time intervals. The midpoint time of each urine collection was used for statistical analyses. Modified from Ackermann et al. [16] with permission.