BOB HIRSHON (host):
E-readers and sleep cycles. I’m Bob Hirshon and this is Science Update.
Instead of lulling you into a relaxing night of sleep, curling up with an e-reader might be causing sleep disturbances. In research conducted at Brigham and Women’s Hospital, researcher Anne-Marie Chang, now at Penn State, found that volunteers who read books on e-readers had different sleep patterns than those who read print versions of the same books.
ANNE-MARIE CHANG (Pennsylvania State University):
It took them longer to fall asleep, their melatonin levels were suppressed and they felt sleepier the following day.
Like televisions, computers and mobile phones, the light emitted by e-readers is brightest in the blue range, and scientists already knew that blue light affects the brain’s production of melatonin— a brain chemical that controls sleep cycles. As a result, Chang recommends avoiding all screens at bedtime. The study appears in the Proceedings of the National Academy of Sciences. I’m Bob Hirshon, for AAAS, the science society.