SIMPLE MATH:
MORE DAYTIME LIGHT = CHARLIE JARBOE
& MARIANA FIGUEIRO
Lighting Research Center, Rensselaer Polytechnic Institute
How can lighting help us during this pandemic? BACKGROUND Light is the major synchronizer of circadian rhythms to the local position on Earth, essentially telling the body what to do and when to do it. Cycles of sleeping and waking, feeding and fasting, the regulation of core body temperature, blood pressure, and the secretion of hormones are just a few examples of circadian rhythms. Bright light (> 500 lux)
10
— designing lighting
received at the eyes early in the day exerts the strongest influence on adjusting (or entraining) the timing our circadian system to regulate these cycles throughout the 24-hour day. Before the introduction of electric lighting, humans were exposed to bright days and dark nights. Perhaps because we evolved under this strong day-night contrast, we have