Zandimna
Circadian time point 0 is the timing of the nadir of the circadian core temperature rhythm. Light exposure prior to the temperature nadir results in a delay of circadian rhythms, whereas light exposure after the temperature nadir causes phase advances. Note that there is a dead zone in the middle of the day where bright light exposure has no effect on the timing of circadian rhythms. In contrast, melatonin administered in the beginning of the night advances the circadian rhythm, while melaton...
