(NEWSER) – Your iPad or smartphone could well be hurting your sleep patterns, even if you're getting in a full eight hours of shuteye, researchers say—and the effects could be long-term. Over a five-night period, researchers in Boston had some subjects read for four hours a night on an iPad; others did their reading on printed books, with the lights low, the Washington Post reports.
Among members of the iPad group, levels of melatonin, a chemical behind sleepiness decreased. It took them longer to drift off by an average of 10 minutes, the Wall Street Journal reports. And once they did, their periods of rapid eye-movement sleep were shorter.