Getting (or giving) an e-book for Christmas? It comes with a warning.
A new study on the impact of back-lit electronic reading devices before bedtime concludes that readers take longer to fall asleep, have a lower quality of sleep and are less alert in the morning.
Researchers from Harvard's Medical School School in Boston remind us that the bodies are kept in tune with the "rhythms" of day by an internal body clock which, in practice, uses light to "tell the time." But blue lights coming from smartphones, tablets and LEDs disrupt that body clock and can slow or prevent the production of melatonin.
"The light emitted by most e-readers is shining directly into the eyes of the reader, whereas from a printed book or the original Kindle, the reader is only exposed to reflected light from the pages of the book," leader researcher Charles Czisler told the BBC
. "Sleep deficiency has been shown to increase the risk of cardiovascular disease, metabolic diseases like obesity and diabetes, and cancer. Thus, the melatonin suppression that we saw in this study among participants when they were reading from the light-emitting e-reader concerns us."
Leading more than a few nighttime readers to turn instead to something called books, in which the words are actually printed on paper and hard-bound. Wonder of wonders.