Study: Light-Emitting Screens Before Bedtime Disrupt Sleep

jfruh writes: Tablets and e-readers are more convenient in many ways than paper books, but many people have complained that the physical experience of using them isn't as good. And now we have some specific quantification of this fact: a study has shown that people who read text on a tablet before bed don't sleep as well as those who read a traditional book (abstract).

Comments

At a guess . . .

[mmell]

The amount of light entering the eye and stimulating the optic nerve is higher for the tablet. More light == more wakefulness. We're wired that way.

Re:At a guess . . .

[fustakrakich]

There's always the brightness control. I suspect most people set it too high.

Re:At a guess . . .

[SeaFox]

I set mine waaay low when I'm reading late at night. Then again the room lights are also pretty dim, too. It's always surprising how dim it is if I try using it the next day in a fully lit room.

Re:At a guess . . .

[carlhaagen]

It's about light at the blue wavelength - the intensity obviously plays a part, but the wavelength is the primary cause. When the optical nerve receives EM at this wavelength the brain tells the pineal gland to not produce melatonin.

Re:At a guess . . .

[ProzacPatient]

Since most reading you'll do is black text on a white background I always go into accessibility settings and invert the screen so it will be white text on a black background which will emit significantly less light than the former.

Re:At a guess . . .

[Anonymous Coward]

There's always the brightness control. I suspect most people set it too high.

No. That has much less to do with it than the frequency of the light. There is specific blue wavelength that triggers circadian rhythm. Essentially, if you are looking at a screen before bed, you are screwed. (and this seems to include me too)

220V incandescent in a 120V plug tends to produce the light you need to get to sleep. So if you want to read, get a 40W 240V bulb on ebay from China, and use it in your 120V light fixture. It will be a dim, orange 10W bulb, but more than enough to read by. And doesn't disrupt melatonin production.

If you are in 220V country, well, not such an easy solution. Needs a dimmer switch.

And yes, has to be incandescent. CFS, LED, all are terrible. Unless you wish to light your book with red LEDs!

Re:At a guess . . .

[JMJimmy]

and everybody knows melatonin puts you to sleep.

Melatonin is a neurotransmitter involved in triggering sleep, it's also involved in gallbladder function converting cholesterol into bile. What most people don't know though is that it can cause eye damage in high doses (above 0.8mg) if taken regularly. Health food stores sell the stuff in 3mg+ tablets of course.

Re:At a guess . . .

[l0n3s0m3phr34k]

I've made a few "sleep light" things. Nothing complex, one is four blue florecent bulbs all plugged into the outlet-to-plug recepticals. This I can take and plug into whatever room I'm in when I'm trying to wake up. Not just by itself but in addition to the other lights. It's pretty bright and I think it's working. In the bedroom I've got red lights under the bed, and blacked out everything else I can find. I work 10 and 12hr shifts and it REALLY has been helping my sleep cycles.

LED's aren't terrible, they are just "not adjustable" much with wattage. But you can get red / orange LEDs for night-time ambient lighting so when you get up to go to the bathroom you aren't kicked into the "wakeness cycle"

Re:At a guess . . .

[Cinnamon Beige]

I went and poked around medical journal databases. MedlinePlus has little, though it confirms the dosage recommendations, while a bit of work via PubMed located this study which I think may be the correct citation. Its PubMed listing seems to indicate that it's not the sole possibility, though, as do its references.

Re:At a guess . . .

[BarbaraHudson]

Easy solution - get a screen made out of dark matter ... since it's 90% of the universe, what could possibly go wrong?

I had this problem, then I got f.lux.

[pushing-robot]

Just get f.lux.

Re:I had this problem, then I got f.lux.

[carlhaagen]

Same. I'm on 3200K during evening, 3000K before bed. Using the laptop before bedtime no longer affects my sleep, not even the least. The problem with blue light preventing melatonin production is long gone.

Re:I had this problem, then I got f.lux.

[disambiguated]

when things are dark, and you need more light, it dims things.

Exactly the opposite: when things are dark, your pupils dilate and you need less light. Do you turn your smartphone brightness down in bright sunlight?

But brightness isn't the point -- color temperature is. I haven't read the documentation; the software is too simple and easy for that, but the homepage describes what it does. Flux lowers the color temperature at night, which interferes less with sleep. I also find it much more pleasant.

Re:I had this problem, then I got f.lux.

[drinkypoo]

Or for Android, since the summary implies mobile devices, there's Twilight.

Or for Unix, since this is slashdot you fucking savage, Redshift.

On Unix, sadly, only Adobe Flash player detects color corrections and plays your video in proper color. Neither Google nor Mozilla have figured this out for flash video, either. Also, Flash player is the only video player which properly suppresses the screensaver on Linux. What year is it?

Re:I had this problem, then I got f.lux.

[sound vision]

If you flipped it on and then flipped it off 2 minutes later, that's probably why. Like going from an incandescent-lit room to a fluorescent-lit room, it takes a bit for your eyes to adjust to the new color temperature. I use f.lux on a daily basis, and often I actually have to check to see if it's enabled, because it's not immediately noticeable after the changeover and your subsequent adjustment.

Re:I had this problem, then I got f.lux.

[FatLittleMonkey]

It looks weird if you go between day/night settings abruptly. During the normal cycle, your eyes adjust as it fades/brightens, so you barely notice it. Try it for a few days. Since using it, I've reduced the night colour-temperature quite a bit (below 4000K) from where I originally set it (about 4800k), you underestimate just how much your eyes can adjust. (Use the slow-transition, the fast-transition is buggy anyway.)

Also, manually adjust the lat/long to suit your sleep pattern, rather than your actual location.

Next on Bennett Haselton's Blog

[Anonymous Coward]

"The math behind news reporting obvious,primordially old fact" Subtitle: "Algorithmic inspections into primordial facts: Case study: My own experience glimpsing into the cosmos thru words, heavenly turquoise light bathing my retinas in sweet abyss, long into the night, of wordy, frequent contributions".

Re: Always good to have confirmation of the obviou

[bill_mcgonigle]

Twilight on Android.

Also, points to Soulskill for posting this after midnight.

Re:What about...

[mark-t]

1. e-paper has a positively abysmal screen update time

I use my tablet a lot for reading highly technical articles, and I often end up flipping back and forth between different pages of the text while I am reading, usually between a page with a figure or code listing and an explanation that follows or precedes it. I'd rather not add an easily perceptible delay between the time that I slide my finger one way or the other to advance or go back a page and the time it takes to actually show it.

2. e-paper's full color support is poor.

Many of the articles that I read come with slides which I also view on the tablet, and color is very useful at conveying information. Some progress has been made on this front, but for most practical purposes, epaper is generally monochrome.

But certainly, if they ever get around to making a non-emissive display technology with a fast enough screen update time that you can't notice any delay between your actions and when the screen update is complete, and they provide respectable full color support, I'll be all over it. The only reason I use a tablet instead of hard copy at all is portability.

Just get f.lux!

[Radak]

I use f.lux on my MacBook and it's great (also available for Windows and Linux, but I haven't tried those versions). It adjusts the colour temperature of the screen, using your location and the time of day, to match the colour temperature of the natural light of that time of day. I have noticed a significant difference in the quality of my sleep since I started using it. Plus, whenever I happen to get up during the night and want use the computer for something, I'm not blinded by the screen.

Re:Just get f.lux!

[jafac]

just a word about this program - sometimes it gets flagged as spyware. I don't know if it's because f.lux has to know your location (in order to time the local sunset) - or if there's something else going on. There are some other programs. There is g.lux, and redshift, for starters.

Re:Just get f.lux!

[Radak]

f.lux isn't designed for outdoor use (although there's no reason you couldn't use it there). The idea is that the light coming off your screen matches the colour temperature of the natural light you'd be receiving if you were outdoors (and whatever might be coming through your windows), so that your brain's neurochemistry (melatonin in particular) matches what it should be doing at that time of day, helping you maintain a natural circadian rhythm, which it seems to accomplish in spades.

Re:Just get f.lux!

[Radak]

I can't speak for the Windows and Linux versions, but I know from Little Snitch that the Mac version attempts to talk to port 443 on their webserver when it starts up, presumably for an update check. Additionally, it attempts to contact doubleclick.net and googleapis.com when you search for location. I just block all this traffic and haven't seen any adverse effects.

Thanks for the pointers to g.lux and redshift. I'll check those out and see if they offer anything better for me.

E-Reader does work for some technical stuff ...

[perpenso]

I understand what you are getting at. I'll use an iPad Retina or laptop during the day to check technical books, reference manuals and other documentation.

However when reading at night its generally a more traditional book (history, sci fi, etc) on a Kindle PaperWhite, in my opinion, its equivalent to a paper book but more convenient. I feel it is a better experience even when compared to the lightest color tablets. Certainly it will vary from one technical field to another but I've had surprisingly good results when reading programming and software development books on the PaperWhite, not as good as a higher resolution color tablet but better than I expected and acceptable with respect to the illustrations and diagrams and such. Then again I haven't tried something like the latest edition of Foley and van Dam (a computer graphics text).

I see the refresh you speak of but its less than turning a paper page of a real book. As for the time you believe you are saving, maybe the faster refresh of a color tablet is not a win once you consider the sleep disruption and also the lowered productivity that results?

Misleading summary/abstract

[reve_etrange]

They used iPads, so this paper isn't really about e-readers in general, just tablets.

In Other News...

[Kuroji]

Related studies have found that the main reason light-emitting screens keep people from sleeping is because they don't ever fucking shut them off and the next thing they know it's 5:36 in the bloody morning!

Yeah me too

[codeButcher]

I sometimes work into the night ("flow"). Other times I read a while in bed on my (big-screen) phone. I use f.lux on the computer, Bluelight Filter on android - other apps have been mentioned.

The science seems to be fairly well understood for a number of years, long enough to develop these apps. See e.g. http://en.wikipedia.org/wiki/M... for pointers, http://en.wikipedia.org/wiki/C... may also be of interest (other effects than light on sleep).

Four Hours of Reading?

[shambalagoon]

In the study the people read for four hours before sleeping. I love reading as much as anybody, but is this a realistic scenario? I'd be more interested to see the sleep disruption from 30 minutes to an hour of reading on light-emitting screens before sleeping.

Re:Four Hours of Reading?

[PPH]

Four hours of H.P. Lovecraft will keep anyone awake.