Light from smartphones lowers sleep hormone

Here is one more compelling reason why parents should not allow kids to use smartphones, tablets and video games, especially before bedtime. With a recent study suggesting that 96 percent of teens use at least one high-tech device in the hour before bedtime, the researchers have cautioned parents against the use of light-emanating devices at night.

The bright light of these devices is capable of lowering levels of melatonin, a hormone that prompts sleep. The study says puberty and changing sleep habits go hand-in-hand, as growing kids start to push for later bedtime.

It would be an understatement, though, to say that the warning is only meant for growing kids. It is just a question of tolerance and adults’ sleep also get disturbed proportionately if they use electronic gadgets before sleeping.  Study shows that not using smartphones and computers at night helps fight insomnia in adults.

The effect was most pronounced for kids just entering puberty, with nighttime melatonin levels suppressed by up to 37 percent in some cases, the investigators found.

“The message is that we really have to be careful about protecting our especially young teens from light at night, which means parents need to get all screens out of the bedroom, because ultimately they can be quite damaging to a child’s capacity to get enough sleep,” said study co-author Mary Carskadon. She is a professor of psychiatry and human behavior at Brown University’s Alpert Medical School, in Providence, R.I.

To some degree, the shift is likely prompted by several social factors, including the loosening of parental restrictions, budding friendships and media. But scientists believe that biological factors also play a role, as a child’s internal sleep clock starts to change.

At the heart of that change is light sensitivity, said Carskadon, who’s also director of the Sleep and Chronobiology Research Laboratory at the E.P. Bradley Hospital. Her team theorized that puberty increases a child’s sensitivity to light at night, causing melatonin levels to stay low and delay sleep. Light From Smartphones, Tablets May Lower Sleep Hormone in Kids WebMD