THE PROBLEM WITH ARTIFICIAL LIGHT: Screens May Be Terrible for You, and Now We Know Why. “A fast-growing body of research has linked artificial light exposure to disruptions in circadian rhythms, the light-triggered releases of hormones that regulate bodily function. Circadian disruption has in turn been linked to a host of health problems, from cancer to diabetes, obesity and depression. . . . Just how much health risk can be attributed to artificial light rather than sleep disruption? If breast cancer rates jump 30 percent in women who work at night, and prostate cancer rates nearly triple in men, what proportion of that circadian disruption comes from artificial light rather than sleep cycle problems? And just how much blue light must be absorbed before things get risky: a few minutes a night or a few hours, a few years or a few decades? These are now pressing research questions, yet it may be difficult to know for sure.”