Does using tablets and backlit eReaders at night lead to sleep deficiency and damage health?
According to findings published in the US journal Proceedings of the National Academy of Sciences, blue light, the wavelength common in smartphones, tablets and LED lighting, can disrupt the body clock and slow or prevent the production of the sleep hormone melatonin.
The study found that using light-emitting electronic devices for reading, communication, and entertainment before bedtime meant it took longer to fall asleep, suppressed levels of the sleep-promoting hormone melatonin and reduced or delayed the amount of REM sleep. And we’re not as alert the following morning!!
Results were based on 12 people locked in a sleep laboratory for two weeks. The results were concluded after taking blood samples from participants who spent five days reading from a paperback and five days from an iPad.
Lead researcher Prof Charles Czeisler said: “The light emitted by most e-readers is shining directly into the eyes of the reader, whereas from a printed book or the original Kindle, the reader is only exposed to reflected light from the pages of the book. Sleep deficiency has been shown to increase the risk of cardiovascular disease, metabolic diseases like obesity and diabetes, and cancer. Thus, the melatonin suppression that we saw in this study among participants when they were reading from the light-emitting e-reader concerns us.”