E-Readers Foil Good Night’s Sleep

https://hms.harvard.edu/news/e-readers-foil-good-nights-sleep

by walterbell • 11 years ago

8 14 11 years ago

hms.harvard.edu

koralatov• 11 years ago

The title of the article is misleading, as the participants were reading on a tablet, not an e-reader. ("During the two-week inpatient study, twelve participants read digital books on an iPad for four hours before bedtime each night for five consecutive nights.")

Having used an iPad, a Kindle, and a Kobo, I know from experience that there's a huge difference in the quality and intensity of light emitted by the devices. At its lowest setting, an iPad emits much, much more light than an e-reader at its lowest setting, and the e-readers I've used have to get above 25% or so before they begin to match the light intensity of the iPad at its lowest setting. The displays also differ in the way they're lit: tablet LCDs are backlit, and e-readers are generally front-lit, with the light being pointed at the screen and bouncing back off it.

I wouldn't be surprised if the blue/white light used on e-readers also affects sleep, but I think a study needs to be carried out using those devices before it can be concluded that they do.

walterbell2• 11 years ago

The Marvin e-reader app on iOS can control color temperature, to reduce blue content, http://www.appstafarian.com/marvin.html

It's unfortunate that iOS does not have platform-wide support for adjusting color temperature.

coolandsmartrr• 11 years ago

The title could be misleading. It's light-emitting e-readers that affect sleep cycles, especially iPads which they used in the study.

That means my sleep shouldn't be distracted significantly just because I read on my non-backlit Kindle.

manicdee4• 11 years ago

It's even more misleading than that. The study really only demonstrated that having a spotlight shone in your face for four hours before going to bed will interfere with your sleep.

rahimnathwani• 11 years ago

The headline doesn't reflect the content: "Although iPads were used in this study, researchers also measured other devices that emit blue light, including eReaders, laptops, cell phones and LED monitors."

So, they did a user study using iPads, and only measured the other devices. They then claim the results apply to those other devices.

TFA didn't have a link to the paper (as far as I could tell), but it's here: http://www.pnas.org/content/112/4/1232.full?sid=a0e8cb09-0a5...

"The randomized, crossover protocol design consisted of two conditions: (i) reading an LE-eBook (iPad; Apple Inc., Cupertino, CA) in otherwise very dim room light for ∼4 h before bedtime for five consecutive evenings, and (ii) reading printed books in the same very dim room light for ∼4 h before bedtime for five consecutive evenings (Fig. 1)."

This seems like a strange test. When I read a physical book in bed, I need more light (e.g. from a lamp) than when I'm reading on a Kindle or an iPad (which I often read with the lights off, which also means I can turn the backlight to a low setting).

manicdee4• 11 years ago

Even stranger is that the iPad was fixed in position on the table, with brightness set to maximum.

The maximum brightness on an iPad means you can read the screen in broad daylight. I can not see how this level of brightness lends itself to bedtime reading in a dimly lit room.

wlesieutre• 11 years ago

Crappy choice of terminology for this article. They're talking about reading in iPads (or other backlit LCDs, presumably).

Was hoping for some insight on frontlit eInk readers like the Nook Glowlight or Kjndle Paperwhite.

dade_• 11 years ago

"Backlit devices" would be much more accurate, but I doubt this information is news to anyone here. I have a Kobo, but use an external LED clip light. To solve the problem, I popped the external light open and replaced the "white" LED (which are actually blue) with and RGB LED and only connected the red and green LED. It is plenty bright for reading, but I am surprised that I've never found an actual product that does this.

Spittie• 11 years ago

Interesting, I've been wondering about this myself lately, as I've started to read on an e-book reader ~30 minutes before going to sleep as a part of my routine. Too bad they only used iPads for this study.

I wonder if it's better for my sleep to read a "normal" book with the lights on, or if it's better to read with an ereader with the minimum amount of brightness on. I think I receive less blue light with the second case, but maybe it's more direct into my eyes? I also wonder if there is a difference between a "normal, backlit screen" and an "e-ink frontlit screen" at the same brightness.

And it's a bummer that no-one sells an ereader with a "flux" mode.

walterbell2• 11 years ago

You can buy ambient lighting that has low blue content, e.g. the "Evening PM" version of the GE Align, http://www.amazon.com/gp/product/B00PLR3M0M

nielsk• 11 years ago

E-Readers is wrong. The study used as a "light-emitting" book an iPad (p. 1235). So it is tablets and smartphones. It is not even clear to me if a Kindle Paperwhite would fall into the category.

manicdee4• 11 years ago

The Kindle Paperwhite can not be turned up as bright as the iPad can, which would mean that the results of this study do not apply. The results of the study are basically that having bright light shone in your eyes interferes with your sleep (nothing to do with iPad vs book).

lamby• 11 years ago

As all the other commenters have mentioned (separately for some reason..), this is a misleading title.. However, I'd still read some fiction on a backlit e-reader than go through my emails and TODO list on my laptop from the relaxation point of view.

manicdee4• 11 years ago

Note: the people reading paper books were allowed to adjust their position and the book's position while reading.

The people reading the "LE-eBook" (i.e.: iPad) were forced to do their reading with the iPad locked into position and the brightness turned to maximum, for four hours.

I find it hard to accept the study's findings that it was "use of these devices [that] prolongs the time it takes to fall asleep," rather than, say, having a bright light shone in your eyes and not being allowed to shift position while reading for four hours.

The iPad's brightness can be turned down much lower than an equivalent paper book illuminated by a reading lamp. Even better, the iPad's illumination will not disturb your sleeping partner as much as a bed lamp (the latter illuminates the whole room).

I'd like to see this study repeated with paper books vs paper books, with books fixed in place on the table, and one group's books illuminated with a spotlight providing equivalent illumination to the reader's face as the maximum-brightness iPad.

Then run a parallel study with all readers using iPads, with some having the brightness fixed to maximum and others free to adjust brightness to their own comfort.

E-Readers Foil Good Night’s Sleep

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