could be causing restless nights for many who use it to read e-books before lights out. According to the Los Angeles Times, the light that's emitted from the iPad's screen inhibits the release of melatonin
, a chemical that tells your body to wind down for the evening. This holds true for any device that emits unnatural light -- be it a TV or a cell phone. But Frisca Yan-Go, director of the UCLA Sleep Disorders Center in Santa Monica, told the Times that the iPad has a greater effect on preventing the release of melatonin in the body because users hold it so close to their faces. The same, then, goes for cell phones and other gadgets with screens. Thus, watching reruns of 'Family Guy' on the couch is less
likely to keep you up than reading a John Girsham iBook under the covers, because of your eyes' proximity to the light's source.
But you don't have to give up your e-books
. The Kindle and Nook can be used at night with little or no effect on melatonin secretion, Yan-Go says. That's because these devices use e-ink, which doesn't emit light. It also means you can use a Kindle or Nook, unlike the iPad, in direct sunlight -- a crucial fact as summer rears its head. By no means do we think this discovery will cause Apple to lose ground in the e-book market. More than likely, it just means iPad users will look more sleep deprived during the morning commute. [From: The Los Angeles Times