Ebooks at night won’t help you sleep tight, US study finds

Harvard researchers say light-emitting ebooks negatively affect our sleep and lead to next-day grogginess.

Reading a light-emitting ebook before bed is bad for your health, according to a new US study. It warned that use of the devices affected both sleep at night and alertness the following morning.
Researchers from Harvard Medical School’s sleep medicine department put 12 healthy young adults through a two-week experiment, in which the participants would either read a light-emitting ebook for four hours before bedtime or a printed book. Study participants reading a light-emitting ebook took on average almost 10 minutes longer to fall asleep and said they were less sleepy an hour before bedtime than they were reading a paper book.


http://www.theguardian.com/books/2014/dec/23/ebooks-affect-sleep-alertness-harvard-study