The pervasive blue light glow of electronic devices is an impediment to a good night’s sleep. That’s particularly noticeable now, when families are adjusting to early wake-up times for school. Teens can find it especially hard to get up in the morning. For nocturnal animals, it spurs activity. For daytime species such as humans, melatonin signals that it’s time to sleep. As lamps switch off in teens bedrooms across America, the lights from their computer screens, smartphones and tablets often stay on throughout the night. These devices emit light of all colors, but it’s the blue light in particular that poses a danger to sleep. Blue light is especially good at preventing the release of melatonin, a hormone associated with nighttime. CONTINUE READING