eReaders are the enemies of sleep

If you receive gifts of e-books in your virtual Christmas stocking this year, you might want to avoid reading them before bedtime.

Worldwide research shows that exposure to electronic light in the hour before bedtime can impair sleep and alertness the next day, and may have a long-term impact on health, performance and safety. 

Photo by Daniel Suarez via Flickr, Creative Commons

Photo by Daniel Suarez via Flickr, Creative Commons

The cause may be short-wavelength–enriched light emitted by electronic devices, German and American researchers report in a study published today.

Exposure to the artificial light has been shown to raise alertness, suppress the hormone melatonin, and phase-shift the circadian rhythm, our natural biological clock. Dim light, on the other hand, “is a cue for circadian rhythms, allowing for production of melatonin,” noted the study, in the science journal Proceedings of the National Academy of Sciences.

The results matter, they said, because of links “with the increased risk of breast, colorectal, and advanced prostate cancer associated with night-shift work … classified as a probable carcinogen by the World Health Organization.”

Reading an electronic book, the study said, “is likely to increase the risk of delayed sleep-phase disorder and sleep onset insomnia, especially among individuals living in society who self-select their bedtimes and wake times. Induction of such misalignment of circadian phase is likely to lead to chronic sleep deficiency.”

The study noted a survey of 1,508 American adults showed 90 per cent regularly use electronics in the hour before sleep.

Researchers compared the quality of sleep obtained after study participants used an eReader before bed, with the quality of their sleep after reading a printed book. Electronic readers experienced more “reduced evening drowsiness, took longer to fall asleep, and reported reduced morning wakefulness.”

Reference: Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness, by Anne-Marie Chang, Daniel Aeschbach, Jeanne F. Duffy, and Charles A. Czeisler, in PNAS http://www.pnas.org/lookup/doi/10.1073/pnas.1418490112

 

 

This entry was posted in Current Affairs, Gyroscope.

One Comment

  1. Colette Phillips January 2, 2015 at 17:47 #

    This study did not actually use e readers, but an ipad. The conclusions drawn can only be extrapolated to ipads and devices that light up in similar manner. For instance, the Kindle Paperwhite is not backlit, but inwardly lit. Please correct me if I’m wrong, but that is how I interpreted the full article (as opposed to just the abstract). Please note that I am very biased, as I have found it easier to fall asleep with my Kindle and love the little thing to death. 🙂

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