The pervasive glow of electronic devices may be an impediment to a good night’s 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 blues in particular that pose a danger to sleep. Blue light is especially good at preventing the release of melatonin, a hormone associated with nighttime.
Ordinarily, the pineal gland, a pea-size organ in the brain, begins to release melatonin a couple of hours before your regular bedtime. The hormone is no sleeping pill, but it does reduce alertness and make sleep more inviting.
However, light — particularly of the blue variety — can keep the pineal gland from releasing melatonin, thus warding off sleepiness. You don’t have to be staring directly at a television or computer screen: If enough blue light hits the eye, the gland can stop releasing melatonin. So easing into bed with a tablet or a laptop makes it harder to take a long snooze, especially for sleep-deprived teenagers who are more vulnerable to the effects of light than adults.
In a 2014 poll, the National Sleep Foundation, an advocacy organization, polled parents, asking them to estimate their children’s sleep. More than half said their 15-to-17-year-olds routinely get seven hours or fewer hours of sleep. (The recommended amount for teens is 81 / 2 to 10 hours.) In addition, 68 percent of these teens were also said to keep an electronic device on all night — a television, computer, video game or something similar.
Based on what parents reported, sleep quality was better among children age 6 to 17 who always turned their devices off: 45 percent of them were described as having excellent sleep quality vs. 25 percent of those who sometimes left devices on.
“It is known that teenagers have trouble falling asleep early, and every teenager goes through that,” said light researcher Mariana Figueiro of the Rensselaer Polytechnic Institute in Troy, N.Y.
Figueiro investigates how light affects human health, and her recent research focused on finding out which electronics emit blue light intense enough to affect sleep. When comparing melatonin levels of adults and teenagers looking at computer screens, she was astonished by the younger group’s light sensitivity. Even when exposed to just one-tenth as much light as adults were, the teens actually suppressed more melatonin than the older people.
Source: Washington Post