Many people spend time on their electronic devices at night before going to bed. And now, a new study has found that using some of those light-emitting devices can actually interfere with sleep quality and be harmful to your health.
The study, which was from Brigham and Women's Hospital and Harvard Medical School and published in the Proceedings of the National Academy of Sciences, compared reading paper books with e-books before bedtime.
Twelve patients read books on an iPad for four hours before bedtime for five nights. Then, the volunteers read paper books before bedtime for another five nights.
Researchers found that the production of the sleep hormone melatonin was reduced when the group read the e-books.
"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," lead researcher Professor Charles Czeisler told BBC News.
Volunteers took nearly 10 minutes longer to fall asleep after reading iPads than when reading paper books.
The main concern Czeisler said is that sleep deficiency can contribute to several health problems including an increased risk of cardiovascular disease, obesity and diabetes.