A new study done by the Lighting Research Center (paid for by Sharp Corporation, maker of backlit displays) has found that people reading electronic devices with backlit displays are more likely to experience sleeping problems. The Los Angeles Times says the researchers found that reading backlit devices resulted in lowered levels of melatonin, a chemical whose levels in the body control sleeping.
In the study, thirteen volunteers were asked to read material on an electronic tablet computer for two hours, afterwards blood samples were taken from each and melatonin (a hormone produced by the pituitary gland) levels checked. The researchers found that after two hours of reading, levels had dropped by an average of twenty two percent. The researchers say the interruptions lead to changes in the circadian clock, which controls among other things, sleeping, eating and metabolism patterns.
The problem, the researchers say, is that focusing the eyes directly on backlit screens appears to fool the brain into thinking that it’s the middle of the day, rather than nighttime, and the brain appears to adjust by altering melatonin levels.
The researchers also tested volunteers playing games on backlit devices and watching movies and found that all such activities tend to lead to difficulty falling asleep and then staying there as the body tries to adjust to what it feels is the wrong sleeping time. They say that the results of their study matches closely with those found in other research projects where volunteers were subjected to an environment that simulated middle of the day conditions. In those cases, volunteers reported difficult sleeping during the time they were supposed to be sleeping and feeling confused about when they are supposed to be in bed.
The Times says the researchers have been urging manufactures of backlit products to work on models that don’t interfere with sleep, though how that might come about appears to still be an unanswered question. Also, thus far, it’s not clear if those using e-readers that rely on electronic ink to display characters (such as Amazon’s Kindle) succumb to the same problems. They also note that there have been some reports in the media blaming tablet computers for sleepiness in students, which the researchers say showed the highest levels of melatonin alteration of all those people tested. This they say means that educators and parents alike need to educate teens to the impact of reading, or using their tablet computer for other purposes in the hours before going to bed.