In a nutshell, what normally happens is light decreases, your body releases melatonin, and you feel sleepy shortly thereafter. With the advent of artificial li

In a nutshell, what normally happens is light decreases, your body releases melatonin, and you feel sleepy shortly thereafter. With the advent of artificial lighting, we started delaying our dim-light melatonin onset (DLMO). It most strongly responds to blue light, but it does respond to other wavelengths, too, so some people find that any light is too much.