Study Shows Digital Devices Disrupt Sleep Cycles

Little girl with her baby brother watching cartoons on their digital tablet, past their bedtime.

“Good night, sleep tight,
Wake up bright
In the morning light
To do what’s right
With all your might.” 1

By Ajay K. Singh, MBBS, FRCP, MBA
Tuesday, January 31, 2017

Tablets and ipads are now common in the bedrooms of children and adults.  Buxton and colleagues report from survey data that 90% of children obtain less sleep than recommended. The December 2016 article in JAMA Pediatrics on the association between media device use and sleep outcomes should be a “wake-up call” for all parents.

In the article, Ben Carter and co-workers present data from a systematic review and meta-analysis from 20 studies representing approximately 125,000 children age 6 to 19 years. The mean age of their sample was 14.5 years.

Carter et al conclude that looking at a device like an ipad before bedtime effects sleep—making it of poorer quality. Their study also suggests that such devices (and even the presence of them) are associated with daytime sleepiness.

In an editorial accompanying the Carter paper, “Problems Associated With Use of Mobile Devices in the Sleep Environment—Streaming Instead of Dreaming“, Chuck Czeisler and Theresa Shanahan from the Brigham and Women’s/Harvard Medical School point out that these devices may have impact beyond sleep, including on learning and memory, and that perhaps, sleep deficiency symptoms may “mimic those of attention-deficit/hyperactivity disorder.”

Still, while observational data is important, until recently no randomized trials had been performed. In a paper in the journal PNAS, Anne-Marie Chang and colleagues from Chuck Czeisler’s group performed a very interesting randomized controlled trial.

They enrolled 12 healthy adults with a mean age of around 25 years; one-half of study subjects were women. They performed an inpatient cross-over randomized trial where they either asked subjects to either read an LE-eBook (light-emitting ebook on an ipad) or a printed book in otherwise very dim room light for  about four hours before bedtime for five consecutive evenings. They collected data on sleep as well as blood for serum melatonin.

The authors report that reading an LE-eBook before bedtime decreased subjective sleepiness and suppressed the late evening rise of melatonin secretion during the time that the book was being read. They also found that compared with reading a printed book, reading an LE-eBook before bedtime lengthened sleep latency (the interval between lights-out and the timing of sleep onset), total sleep time, sleep efficiency (the percentage of time in bed spent asleep), impacted circadian control on melatonin secretion, and impaired morning alertness.

So what does all this mean? Well, for a start, it suggests that eBook reading is detrimental to sleep and might lead to daytime sleepiness, in both adults and children. It suggests that the physiological mechanism behind this is loss of circadian secretion of the hormone melatonin. As well, in adults and children, sleep deficit might affect performance.

Reading a book to your kids or reading an actual book, while old fashioned, may actually be best!

Study for the obesity medicine boards online with HMS instructors.


1Volumes 24-26 of Teachers’ Monographs: Plans and Details of Grade Work, 1917 Vol 24-26 p 138

Ajay Singh, MBBS, FRCPDr. Ajay K. Singh is the Senior Associate Dean for Global and Continuing Education and Director, Master in Medical Sciences in Clinical Investigation (MMSCI) Program at Harvard Medical School. He is also Director, Continuing Medical Education, Department of Medicine and Renal Division at Brigham and Women’s Hospital in Boston.


Leave a Reply