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 basically, computer screens, iPad screens, iPhone screens, etc. mess with your pineal gland, which is essentially, if you believe in such things, your “third eye”—which means that the harmful effects from the screen light may extend way beyond simply sleep function.
Which is why it is super-hard for me to get relaxed and read on a tablet, write on a laptop, listen to music on my phone, etc. Much less do any sort of editing work directly on these devices. Which is why I always feel rather foolish still printing stuff out. But maybe not that foolish.
Recently, I purchased a small “regular” (non-electronic display) alarm clock to keep in my bedroom, as well as a sound machine in case I need extra audio help falling asleep. The phone screen stays in a drawer until the morning. In a future post, I’ll update as to whether this strategy has given me any benefits.