For those of us who are terrible at sleeping, reading before bed — or in the middle of the night, when sleep just won’t come — can be extremely helpful. And, since it’s almost 2015, much of this reading now occurs on various e-reading devices. A new study in Proceedings of the National Academies of Sciences, though, suggests that this might be counterproductive when it comes to getting healthy sleep.
For two weeks, 12 participants read either a paper book or a book on a (light-emitting) iPad for five days, then switched it up and did the other method of reading for five days. The press release has the grim details of the effects of e-reading before bed:
The iPad readers had reduced secretion of melatonin, a hormone which normally rises in the evening and plays a role in inducing sleepiness. Additionally, iPad readers had a delayed circadian rhythm, indicated by melatonin levels, of more than an hour. Participants who read from the iPad were less sleepy before bedtime, but sleepier and less alert the following morning after eight hours of sleep. Although iPads were used in this study, BWH researchers also measured other eReaders, laptops, cell phones, LED monitors, and other electronic devices, all emitting blue light.
It sounds like paper books are the best bet for before-bedtime readers. Throw that on the pile of the million other things that apparently make it harder to sleep.