Using an e-reader before bed hurts your sleep and health, according to a study published on Monday in the journal Proceedings of the National Academy of Sciences.
In the study, 12 people in a sleep laboratory spent five consecutive nights reading a book for four hours under a reflected light and five evenings reading from an iPad for four hours. For two weeks they all had to go to bed by 10 p.m. and wake up at 6 a.m.
The researchers from Brigham and Women’s Hospital and Harvard Medical School found that those who looked at the iPad for hours had suppressed evening levels of melatonin. It took these readers 10 minutes longer to fall asleep and they had nearly 12 minutes less REM sleep, which is connected to memory consolidation.
The next day these e-readers were more tired than they were after reading a paperback. When going to bed that night, the increase in melatonin happened 90 minutes later, signifying a shift in the body’s circadian cycle.
The study showed that using a tablet or e-reader before bed not only damaged the subjects’ sleep, it could damage their health. Long-term suppression of melatonin by light exposure before sleep has been linked to increasing the risk for some cancers, obesity, and diabetes.
Experts suggest minimizing light-exposure at night to sleep better. They discovered the quality of short-wavelength light from computer devices, such as the iPad, Nook, and Kindle Fire, changes the body’s circadian clock.
Neuroscientist Anne-Marie Chang, a biobehavioral health expert from Penn State University, described the implications of this study. “There are so many things we don’t know about how these devices affect our health and our sleep. How much time before sleep do you need to kind of wind down? Is there a window when this light won’t have that effect? Those are very interesting questions that need further investigation.”
Doctors are especially concerned with how these devices affect teenagers, who naturally have a late body clock and are already sleep deficient.
However, using an e-reader before bed can harm anyone’s sleep and health. So if you like to read books or the news at the end of a long day, be careful how and when you do it.[Photo Credit: Javier Leiva]