(Wired) Since forever, life on Earth was governed by the cyclical light of sun, moon and stars. Then along came electric light, turning night into day at the flick of a switch. Our bodies and brains may not have been ready.
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. "Everything changed with electricity. Now we can have bright light in the middle of night. And that changes our circadian physiology almost immediately," says Richard Stevens, a cancer epidemiologist at the University of Connecticut. "What we don't know, and what so many people are interested in, are the effects of having that light chronically."