If you're looking to get a good night's sleep, researchers suggest staying away from light-emitting devices like iPads and e-readers before going to bed.
A study out of Brigham and Women's Hospital in Boston found that using those devices can delay the onset and characteristics of sleep and can also shift your natural clock, the Los Angeles Times reports. For the study, 12 people checked into a sleep lab and stayed there for two weeks, spending five nights in a row reading a book for four hours under reflected light and five evenings using an iPad for four hours. All had a required bedtime of 10 p.m. and a wake-up call at 6 a.m.
Blood tests revealed that those who read from the tablet had suppressed evening levels of melatonin and a shift in their circadian cycle. It also took those who used the e-readers 10 minutes longer to fall asleep, and they had almost 12 minutes less rapid-eye movement sleep. Researchers plan on taking these results and using them as the foundation for other studies. "There are so many things we don't know about how these devices affect our health and our sleep," neuroscientist Anne-Marie Chang said. "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."