Figure 1. Raster plot of the experimental protocol.

During the two baseline days sleep episodes were scheduled from 00:00 to 08:00 Thereafter, the sleep-wake schedule was advanced gradually resulting in a 10 hour advance of the sleep-wake schedule. Sleep episodes on day seven and eight were scheduled from 14:00 to 22.00. During scheduled sleep episodes, participants were exposed to darkness (<0.02 lux). During waking hours the participants were exposed to ∼90–150 lux moderate light. During the bright light treatment episodes, the moderate light participants remained in moderate light, whereas the bright light treatment participants received ∼10,000 lux of light. Both moderate light and bright light treated participants participated in dim light work simulations.