Question of the Week

Would reading from a screen keep me awake?

Sun, 22nd Apr 2012

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Question

Christian Lang asked:

Hi Chris.

 

Love the show. My name is also Chris, and my birthday is 16th Jan too!

 

My question is about those electronic book readers.

 

I occasionally have trouble sleeping, and find that reading a book before bed really helps with this. I was considering getting an e-book reader, but got thinking:

 

Would the light of the screen stimulate your brain in a way that would prevent you from becoming tired?

 

 

Answer

We put this question to Professor Debra Skene from the University of Surrey:

Debra -   I do studies on light and sleep.  We know that light can affect alertness and it can affect your ability to sleep.  We know that it in fact stimulates receptors in the eye that are particularly sensitive to blue light.  This light information then is sent all around the brain and can affect how tired you are and possibly, your ability to sleep.  So I would say, if you had very bright light in your bedroom and we know this from studies, that it in fact delays your sleep time and keeps you more awake.  Now about electronic books, they're not very bright in terms of the intensity of light and so, I would suspect that the light levels are too low to really affect your sleep.  If you wanted to use a computer that had a very bright blue screen, this may keep you up.

A user viewing an electronic page on an eBook-reading device - a $100 Laptop prototypeHannah -   Computer screens, televisions and bright lights all emit a strong blue light of high enough intensity to stimulate.  So, reading from a backlit screen of a laptop or tablet could lead to sleepless nights.  However, most E-Readers use special electronic paper technology which has no backlighting and utilises reflected light in exactly the same way as normal paper.  Because of this, an E-Reader should only keep you awake if you can't put it down.

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I use an e-book reader with magnetic ink (not TFT) in bed and I don't notice any difference with a normal (paper) book. I suppose because it is not a screen that is refreshing itself so many times a second it doesn't affect as much. albionado, Tue, 24th Apr 2012

but is your table lamp shining in your ear ... http://www.thenakedscientists.com/forum/index.php?topic=43345.0 RD, Tue, 24th Apr 2012

If you had an e-book reader that had a backlight, then you could turn off the rest of the lights in your room.
Then adjust the backlight until it wasn't too bright.

You should get less "extra" light than you would ordinarily get by using a bedside lamp.  You would, however, still be focused on the center of the illuminated page.

Could you adjust it so the page was no brighter than an ordinary piece of paper illuminated by a lamp?

You might be able to decrease the incident light even more by changing the page to white on black, rather than black on white.

Can you get college textbooks in E-Reader format?  They'll knock you out quickly!!! 
CliffordK, Tue, 24th Apr 2012

Hannah and Debra's answers seem to draw opposite conclusions.

Do the reading lights that clip onto your book have less of an effect on sleep?

Do different types of bulbs have an effect? Is a bed lamp + book worse then a backlit e-book reader? davekm, Tue, 5th Jun 2012

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