Light Exposure and Circadian Biology: How Daytime Illumination Regulates Mood, Sleep, and Metabolic Health
“Daylight” is more than a visual cue: it is a primary environmental signal that entrains the circadian timing system, coordinating sleep–wake behavior, endocrine output, cognition, and metabolic regulation. In chronobiology, light is transduced by specialized retinal photoreceptors—classically melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs)—which project to the suprachiasmatic nucleus (SCN) in the hypothalamus. The SCN… Read More »