Some people might say that sleep is wasted time. Clearly, they haven't heard that sleep is where you put your memories away for safe keeping, give your genes a chance to chill out, and give your brain a rinse.
That's why taking our phones to bed with us is such a problem. While they may seem innocent, the screens we lavish with our waking attention sully our slumber. They illuminate us in all the wrong ways.
"Light works as if it’s a drug, except it’s not a drug at all," George Brainard, a neurologist at Thomas Jefferson University in Philadelphia, told the New York Times.
This is because light has a relationship with two of our most dichotomous hormones: melatonin, which helps us drift off to sleep, and cortisol, which gets us ready for action. As io9 notes, evolution is at work here: we used to have a pretty regular rhythm of lots of light and little light, what with the movement between sunny days and starry nights. That light signaled to our bodies when to release melatonin and when to release cortisol, thus priming us for rest and activity.
But that is no more.
Now we have a whole host of well lit nighttime distractors, with most every device employing LEDs, which it turns out are absolutely terrible. More and more research shows that LEDs give off a blue wavelength of light, which is especially suited to suppressing your melatonin levels and thus not allowing you to nod off.
But it's not just that we stay awake longer thanks to our devices and the content therein. Once we get to sleep, we're getting worse rest: the unnaturally raised levels disrupt our sleep and mess with our body-fat and inflammation levels.
"But if our rooms are dark at night .. our bodies pump out the much needed melatonin," says George Dvorsky, writing for io9. "Moreover, our melatonin levels are regulated according to the amount of exposure we had to light during the previous day."
In this way, getting a solid night's rest is similar to staving off Seasonal Affective Disorder: you want to give yourself as much sunlight as possible as early as you can during the day, since that will provide a super strong signal to your hormones that you really do need to be awake. Then when it gets late enough, you'll really be able to sleep—so long as you keep your phone far from your pillow.
Hat tip: io9