Figure 2.

Effects of sleep-wake cycle and light exposure on rhythmic variables. (A) Daily rhythm of core body temperature is altered when sleep occurs in phase (at night) versus out of phase. Recalculated from Dijk and Czeisler (1995). (B) Rhythms of plasma melatonin and cortisol are not much affected by sleeping in phase (during the night) or out of phase (during the day). Data from Archer et al. (2014). (C) Frequency distribution of the acrohases of rhythmic transcripts in whole blood when sleeping in phase (blue) and out of phase. From Archer et al. (2014). (D) Individual-level dose-response curves for melatonin suppression and light levels. Blue, high-sensitivity individual; red, low-sensitivity individual. From Phillips et al. (2019).