Exposure to Backlit Displays Reduces Melatonin Production 192
alphadogg writes "Researchers have discovered that relatively little exposure to tablets and other electronics with backlit displays can keep people up at night by messing with their circadian rhythms. The study from the Lighting Research Center at Rensselaer Polytechnic Institute showed that a 2-hour exposure to electronic devices with such displays causes suppression of the melatonin hormone and could make it especially tough for teens to fall asleep. The study, funded by Sharp Laboratories of America, simulated usage of such devices among 13 people using special glasses/goggles and light meters"
Orly? (Score:2, Funny)
My eyes! The goggles, they do nothing!
Sample size too small? (Score:5, Interesting)
Surely 13 people is too few to draw meaningful conclusions?
Re:Sample size too small? (Score:5, Informative)
Surely 13 people is too few to draw meaningful conclusions?
Yes. Especially if not compared to people reading a book under a 60 watt incandescent light bulb.
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Yes. Especially if not compared to people reading a book under a 60 watt incandescent light bulb.
You must be somewhere with 110-120V mains.
60W is way too bright a bulb to use for reading in areas with 220-240V, unless you sit in the next room.
As I remember this study as described on public radio last week, there were comparisons to incandescent lights, and also an interview with someone who had studied the effect of difference in color temperature and filtered frequencies.
My night time reading? Mostly halogen lamp and e-ink. Previously LCD and green backlight. I have still not found any device tha
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There's no difference in light output by a lamp with the same technology and the same power but with a different voltage. Or were you trying to be funny or sarcastic ?
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Not funny, not sarcastic, just confused. Thoroughly.
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This sentence puts rather silly images into the minds of Americans who read it. This side of a pond a torch is less a battery powered light and more a flaming stick.
Unless of course, that's what you meant. In which case all I can say is "NICE!"
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Yes, this is really junk science, but I believe there are other studies that show similar results - see http://stereopsis.com/flux/research.html [stereopsis.com] for a list, including links to the full papers (the site is for F.Lux which I really recommend to adjust colour temperature to get more sleep, for Windows, Mac and Linux, and jailbroken iOS).
N = 13? (Score:5, Insightful)
Re:N = 13? (Score:5, Insightful)
Furthermore, why didn't they just use actual backlit displays instead of some approximation? It's not like there is a shortage of them.
Re:N = 13? (Score:4, Informative)
Because they wanted to control the exposure. People use tablets differently. Different distances, different brightnesses, different sized font (larger black letters means less light emitted), different tablets=different displays=different wavelengths emitted.
Too small of a group, but an interesting start.
bad test then (Score:3)
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Well, one of the things to consider when comparing tablets, monitors, and TVs is the percentage of light hitting the retina. While monitors and TVs have more area and thus put out more light than tablets, they are much farther away. For example right now my 19" work monitor is an arm's-length away (~3 feet), while a tablet will be a foot, maybe less, from my eyes. So even though a 10" tablet has a fifth of the area, under the inverse square law I'm actually getting twice the light hitting my eyes. And T
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Control the conditions accurately, and limit the variable to the amount of light, not the content.
Reading RSS feeds for 2 hours might keep you much more stimulated than watching a movie, or podcast, or reading an ebook.
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You can't determine statistical significance by looking solely at the sample size. There's actual math involved, and they did that math.
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So, if I were to give thirteen people a pill, and ten of them grew wings and flew away, you would complain that my study hasn't proven that my pills can make people grow wings?
I don't know or particularly care whether or not the study in the article is significant, but it's ridiculous to hold up sample size as the end-all-be-all of what determines significance.
Even better! N = 1 (Score:3)
Re:N = 13? (Score:5, Interesting)
Apart from my joke response, yes, N = 13 is way too small here. Not only that, but the circumstances are questionable as in to how the light was administered. No tests have been done with other light sources generating other spectrums either.
Someone I know has done some rather ground breaking studies in the past, resulting in Philips selling light therapy lamps to cure winter depression. This was the first, or at least the first serious commercial supplier of such lamps, working with clinically proven effectiveness. I know what type of things he had to study to come up with what exactly works and what doesn't, so he would have scientific proof as well as proper clinical tests to prove that the light therapy fixtures he came up with actually worked and what was the "effective ingredient". He also had to make them in such a way that using them would not be too much of a burden to people, getting a usable balance between comfort while the light was on and duration. The higher the light intensity, the shorter exposure required.
One of the things he found, was that below a threshold, your body simply wouldn't react when it came to winter depression treatment. For sleeping (another study he's continuously working on), however, any light source he tried, was an influence, even at very low intensities. He found that things like dream intensity, REM patterns and all that increased when people were in a totally dark room. Even with your eyelids shut, your body still reacts to the light.His most recent study found that by exposing senior citizens to a high dosage of "day light" slows and even can improve conditions like dementia and is very effective against depression.
For all these, to get absolute proof, he had to do double blind field tests on large control groups, in their natural environments, because the plain effect of just exposing them to a test was itself an influence already. Also, as mentioned before, the spectrum and getting over a certain threshold was significant in the senior citizen experiment. He had to do tests in several elderly homes for long periods of time, using different light sources and amounts of light per center, for 6 months time and gather all the data on depression, dementia, number of complaints, amount of people taking an afternoon nap and all that, plus the comparison to the situation a year before, to get any significant data to work with. All in all, his study in senior citizens used more than a thousand subjects. Even with that number, it was hard to get to a level of clinical proof that using intense artificial daylight exposure inside elderly homes was beneficial to the health of the inhabitants.
For the sleeping pattern tests, he is exposing people to different intensities and spectrums for months, using dozens of test subjects each year, for years in a row. People tend to have different sleeping patterns depending on how their day went, the temperature, their general health and the season already. It was common sense to assume that and he quickly found out that the deviation was such that he had to work with large groups and take a lot of samples to deal with that. In order to get any significant results, he'll have to figure out what the standard deviation is per subject, for the entire group and use that to come up with base levels in which he can find differences that can only be attributed to his light testing.Now, how do thirteen lab monkeys with apparatuses stuck to their eyeballs just before they were sent to bed compare to that again?
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As an expert reviewer, it is sometimes necessary to ensure a paper is rejected. This can sometimes be achieved by highlighting improper statistical practice. This technical note provides guidance on how to critique the statistical analysis of neuroimaging studies to maximise the chance that the paper will be declined. We will review a series of critiques that can be applied universally to any neuroimaging paper and consider responses to potential rebuttals that reviewers might encounter from authors or editors.
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Depends what you're using the results for.
If you're arguing that it's too small to be definitive, you're right. It's too small to generalize to the general population.
However, if it's an initial study to see if there *might* be something worth studying (people have been arguing that exposure to screens before bed ruins sleep, after all), then a small sample might be fine to see if it's even worth studying. Rather than spend lots of money studying lots of people and co
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To be fair, the phase response curve is well known and well understood. If 100% of your 13 people saw shifts in it, I think you could have a statistically significant result. You could for instance say that there's a 95% chance that at least 80% of people are so affected, assuming your sample was properly diversified. And of course it's not enough to say "proven beyond any shadow of a doubt" but it's certainly enough to say "that's funny..." which is the more interesting result to an experiment anyway.
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Re:N = 13? (Score:4, Informative)
the omitted cases were due to not generating enough saliva for a melatonin assay. probably not much worry of confounding there.
it doesn't prove a whole lot, if anything. we already knew that blue light suppresses melatonin, and they give the predicted effect in the study along with their measurements. annoyingly, they don't give the two-hour theoretical effect, which is the regime in which they have statistical significance in their results. neither do they formally compare the tablet-only effect to high-blue-light (enforced by goggles) effect, but it's pretty obvious that the tablet isn't as bad. which, of course, isn't surprising since the lumens are lower.
conclusion: it's an almost completely useless study, but the statistics they give seem legit enough. they don't do multiple comparisons correction, but if they did, the two-hour effect would still be significant.
look, guys, if an experiment shows a statistically significant effect which also mostly conforms to the predicted effect (and there aren't blatant design errors), then there isn't much to complain about. i could, quite likely, have done this with n=6 (two for each treatment) and still gotten significance.
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fuck the paywall. here's the table. the intervals for measured melatonin suppression are +/- one standard error.
http://tinypic.com/view.php?pic=33bfl8o&s=6 [tinypic.com]
I can attest... (Score:5, Interesting)
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FTFM (Score:2)
Yah the melatonin helps you sleep but the zombie nightmares get much more awesome.
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Yah the bath salts won't help you sleep, but the zombie reality is truly hyped to the max.
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Haha, solution is to pop a pill. I take it you're an American? No offence, but that seems to be the American way...
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And don't forget about our top shelf security
Wot? Is that why you can feel safe walking the streets at night, leave your home door unlocked, and there are next to no murders and assaults compared to other Western countries?
Of course, you might mean mandatory stickers saying "Warning: The top shelf is not meant for storage. Keep away from children and animals. Do not use if damaged. Failure to follow these safety instructions may lead to injury or death. Known by the state of California to contain substances that may cause cancer."
In which case,
Worry about it in the morning (Score:4, Funny)
I'll worry about this in the morning.
And this is different from TV how? (Score:5, Insightful)
In breaking news:
"Researchers have discovered that relatively little exposure to television and other electronics with backlit displays can keep people up at night by messing with their circadian rhythms."
"Researchers have discovered that relatively little exposure to home lighting can keep people up at night by messing with their circadian rhythms."
And finally:
"Researchers have discovered tha tspending too much time reading obvious 'scientific' reports can keep people up at night by messing with their circadian rhythms."
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I would guess that reading the results of scientific tests would help one to fall asleep.
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A normal computer monitor controls it's brightness in the exact same way nowdays.
LED backlighting has replaced cold cathode flourescent backlighting pretty much universally
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normal
adjective
1. conforming to the standard or the common type; usual; not abnormal; regular; natural.
2. serving to establish a standard.
Just because you don't like it doesn't make it not normal.
Also, just because it has a TV resolution does not make it a TV. Televisions are defined by their built in tuners that conform to broadcast standards, any screen that does not supply it's own video signal is considered a monitor.
I will give you the crappy resolution thing, but we are finally getting that pushed int
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Yes, I miss my CRTs too.
However this conversation was about LCD panels and they were always a tradeoff between small dot pitches and compact size
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Except the flicker you describe occurs at kHz.
Keep telling yourself that you see it. You don't, and biologically can't.
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You actually can see up to a few kHz.
Admittedly, not directly, but if you sweep your eye past a fast flashing light, it becomes a dotted, not solid line.
(The brain tries to turn off the eyes for a hundred or two ms during a saccade (rapid sweep), but this does not quite work.)
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Yeah, shaking your head will allow you to see pulsed/multiplexed stuff, but I'd think a few kHz is really stretching it. I wouldn't think much more than a couple hundred Hz at the most?
Guess it depends on the duty cycle too. I'd imagine 5% duty would be more obvious than 50% or 95% for a given (fixed) frequency.
Guess I'll have to write some LED blinkin' when I get home and see at what speed flailing the LED quits working. (yeah, I suppose speed of the person moving relative to the light matters, also - not
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Yes thats valid for about 60 - 100 Hz. Not kHz.
Especially not say 100 - 250 kHz which you'll get with LEDs.
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Except the flicker you describe occurs at kHz.
That's not the whole story. There are badly implemented displays where the frequency is much lower. For example the one in Acer Ferrari One 200 subnotebook. Even at max brightness I found it annoying (but the glossy coating and small pixel size contributed to it, too). At lower levels the flicker was clearly visible. In a good display I should be done at the kHz range, though.
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Erm by definition, at full brightness there is no flicker from the backlight.
Any effect you noticed must have been something else.
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Depends. LED's are more efficient when overdriven with high current pulses, with the duty cycle controlling the overall power level. 100% brightness might be 5x rated (continuous) current at a 20% duty cycle.
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Erm by definition, at full brightness there is no flicker from the backlight. Any effect you noticed must have been something else.
Many times there is PWM running at max brightness too. However sometimes even in cheap devices there is good quality LED displays with which you don't sense any flicker at any brightness levels.
Pretty Obvious + Plug for Awesomeness (Score:5, Interesting)
I think all /.ers have known this since about age 15. I used to go into a phase where I'd be up every night later and later until I was going to sleep at 6AM and waking up at 2PM. Eventually I'd lose a day and "reset" to a normal time only to inch back later ...
Anyway, here's a plug for the awesomesuace that is f.lux [stereopsis.com], which removes the blue hues from your monitor (since blue light is more associated with circadian rhythm than red) when it's supposed to be night. I am not associated with the makers of f.lux in any way except being a hopeless devotee and mentioning them to anyone within earshot that mentions difficult keeping a normal sleep cycle.
Re:Pretty Obvious + Plug for Awesomeness (Score:4, Informative)
Re:Pretty Obvious + Plug for Awesomeness (Score:5, Informative)
This.
Not that I use f.lux, but the GPL'd Redshift [jonls.dk] on my laptop. When switching it on, it feels like my eyes breathe a sigh of relief - it really is much easier to read off a red-orange-tinted surface at night.
Now if only they'd port it to Android.
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There are a number of 'night mode' apps available for Android. ... though, for the life of me, I can't seem to find any of them. I know for fact I had some installed on at least one of my phones since ICS came out.
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Lux for Android is an auto-screen dimmer, but it also has a 'night' mode with red hues. The red mode is not in the free version, so it will set you back 1 or 2 dollars.
That said, in the evening, I usually read in bed from my Android screen with low brightness and the lights off, and usually I will fall asleep within half an hour; I don't use the 'red mode' for that.
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Thanks, I am trying this out now.
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F.lux is great, works on Windows, Mac and (jailbroken) iOS. One of the downsides of iOS devices as e-readers is that you have to jailbreak to get f.lux installed and not change your sleep cycle.
There's also XFlux, but I use Redshift too on Linux - http://www.ubuntu-inside.me/2009/03/flux-better-lighting-for-your-computer.html [ubuntu-inside.me]
[[http://stereopsis.com/flux/ios.html Now on iOS]] for jailbroken devices - see [[iPhone]] for jailbreaking.
Discussion: http://forum.koohii.com/viewtopic.php?id=5347&p=1 [koohii.com]
Blue light
Uh, yeah. (Score:4, Insightful)
Exposure to light can reduce production of a hormone known to have its production reduced by exposure to light.
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The difference is that the researchers studied the effects of back lit display light, vs indoor incandescent light, candle light, fireplaces, outdoor camp fires, or cave entrance torches...
What I mean is that they lack control groups something fierce.
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Exposure to light can reduce production of a hormone known to have its production reduced by exposure to light.
Not just that. Backlit displays tend to be more blue in color than most home lighting, which is the part of the spectrum that most affects melatonin production (a reasonably well-known effect). Which puts this all in "No shit, Sherlock" territory. Or an undergraduate project.
Welcome to Tautology Club (Score:3)
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I thought it was:
The first rule of the Tautology club is the Tautology club's first rule.
on the hypothesis (Score:3)
Not sure about the sample size...but the Institute backing the research looks reputable enough. (Yes, that matters.)
Anecdotally, I've been turning my TVs and monitors' backlights down after 5 pm for months now. I'm definitely able to get to sleep more easily than leaving monitors at full brightness.
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Best time for such back lit devices is at night. Sigh.
Actually, no. The backlight really just competes with the ambient light. If you're in a bright, sunny room then it's going to require more light shining through the pixels for your eyes to see the picture clearly. If you're in a dark room, there's no glaring of light from other sources to mess up the image...so you need less backlighting to see the image.
Any word? (Score:3)
So, any word on how many man-years of sleep have been pointlessly destroyed by the fact that blue LEDs are now cheap and 'cool' enough to include in assorted consumer electronics devices where low-power greens used to be used?
Maybe I'm just turning into a cranky old guy in my old age; but the old, dim, reds, ambers, and greens in various blinkenlight panels were downright soothing. Now you plug something in(even something designed to be pointed at a movie-watcher's face, FFS) and odds are that a blinding blue point source will burn a hole in your retina. Even a boring domestic-grade pile o' networking gear can put out enough light to read by at night.
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That is actually slowly coming around again. Expensive electronics makers have realized that blue is getting rather overdone and they can look different by not doing it. My Denon receiver uses a red/green light for standby/on and a white display. My NEC monitor does have a blue power light, marketing probably insisted, but you can also change it to be green instead, and change the brightness.
One thing that annoys the hell out of me about the blue LEDs these days is that the manufactures don't seem to apprec
Re:Any word? (Score:4, Informative)
Likewise. I have a Samsung TV with a bright red light that's on whenever the device is off (WHY?) and a Samsung with lighted buttons where the power button's light doesn't ever turn off (WHY?). Both are covered with electric tape.
I swear, every time I think electronics manufacturers can't get dumber, they prove me wrong. The worst part of it is the realization that a simple firmware fix would make the difference between these being great devices and making me want to fly to South Korea and smack all their engineers upside the head repeatedly with a clue-by-four....
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I'm glad the EU banned stuff like that (for saving electricity). My stuff has real off-switches.
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The EU and the "Green Cert" or whatever that stupid environmentally friendly crap are the reason FOR these lights. If you use the remote to turn it off, it stays in "standby" so it has to let you know it's in standby. That way you'll know to turn it all the way off to make the light go off. Some of the Samsung TV's have a "full power" switch by holding the stupid button on the tv. No way to turn the light off from the remote. :) And I hate all peopl
As for the lights on the chargers, that's just stupid.
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It's a standby indicator, they are fairly common on A/V gear. The idea is that you can tell if the devices are ready to accept remote commands, or are hard off. My Denon receiver has two power switches, one which actually powers the unit on to full and the other which is a hard switch. If the hard switch is off, no indicators. If it is one, the soft switch has a red ring indicator showing the unit is in standby. It goes green when it is fully active.
Flat-lined (Score:2)
....again (Score:2)
...Is it just me, or is this story posted every year or two? I thought this was a very well phenomenon by this point...
Has nothing to do with... (Score:2)
f.lux can help (Score:2)
The f.lux program for Windows sits in the system tray and continuously adjusts the blue component of the display based on the time of day.
http://stereopsis.com/flux/ [stereopsis.com]
You can also dose with melatonin caplets a little while before you know you want to sleep.
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I can't prove anything outright, but I feel that using f.lux has helped me sleep more easily. On Linux I use redshift [jonls.dk].
If you set it to the slow transition speed (1 hour), the change is imperceptible. Until you try turning it off, that is. The difference is amazing.
Where is (Score:2)
Where is my 19" eInk display already?
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It's still redrawing.
Sounds good (Score:2)
Now I can stay up longer and write more code.
Well... (Score:2)
...when they invent non-backlit tablets that can play porn, let me know!
backlighting? (Score:2)
Personally, one of the first things I did on my XP system was change that infernal blue color scheme. Olive is so much easier on the eyes. (Yes, changed the wallpaper too.) Likewise I found my android tablet never went dark enough so I turned off Auto brightness - even in daylight I prefer it darker than they set it. (Even at minimum brightness I wish I could turn it down further at night.)
Bad Science... (Score:2)
They did not compare Backlit displays to front lit displays or edge lit displays, so therefore their findings that Back Lit displays are at fault is 100% useless.
I'm betting it's the same old long known knowledge that exposure to bright light will disrupt sleep patterns, they have known this since the 40's.
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I'm betting it's the same old long known knowledge that exposure to bright light will disrupt sleep patterns, they have known this since the 40's.
The 40 ADs, you mean? Probably longer than that.
People have lived north of the polar circle for thousands of years, and dealt with this phenomenon as part of their daily (no pun intended) lives.
From personal experience (Score:2)
Well, that a scientific explanation of what I have observed some time ago: sleeping in after reading/etc on PC is harder compared to sleeping in after reading a book or e-book off e-Ink device.
Was also one of the reasons why I have abandoned long in past the night time TV: it just felt unnatural - and tiring - how it kept me up for no apparent reason.
Probably it is the same reason why I strongly prefer color schemes with dark background for the OS/applications on the PC.
Melatonin Supplements (Score:2)
Always a good idea after late night video games. Much better than not playing them anyways :-)
honest mistake (Score:2)
At first glance, I thought it said "melanin production" and thought, "Well, that explains the Republican Party."
Using a computer before bed can keep you awake... (Score:2)
Really? You think? Most people have known about this phenomon, if not the mechanic, for years. That why they tell people "dont use a computer right before you plan to sleep". or recommend reading a book for 10-20 minutes afterward if you do, to re-relax you.
!News.
Re:Explains a lot (Score:5, Informative)
Now we know why geeks are so pale.
You're thinking of Melanin, not Melatonin.
Maybe it does (Score:3)
I actually can't imagine modding that comment "offtopic". But I am not normal, at al
Re:Explains a lot (Score:5, Informative)
That's melatonin not melanin. Melatonin regulated sleep.
Re:Explains a lot (Score:5, Funny)
That's melatonin not melanin. Melatonin regulated sleep.
I clearly need more sleep. I first thought you wrote "Melatonin regulated sheep."
I suppose sheep regulation could help you sleep - it would make them easier to count.
Re:Explains a lot (Score:4, Interesting)
f course, I've been reading with my iPad and iPhone in bed.
1 I find that the biggest problem of falling asleep with the iPad is that it hurts much more than my iPhone when you fall asleep and it hits you in the nose.
iBooks and Kindle also have a night mode 8) this stops the wife complaining of the LCD glow.
And I've started reading 2312. If this doesnt put you to sleep, nothing will.
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That's melatonin not melanin. Melatonin regulated sleep.
I clearly need more sleep. I first thought you wrote "Melatonin regulated sheep."
I suppose sheep regulation could help you sleep - it would make them easier to count.
Baaaa. Baaaa.
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That's melatonin not melanin. Melatonin regulated sleep.
It used to. Now there's an app for that. Actually, according to the article, just about every app that doesn't turn off the backlight on your tablet is taking over melatonin's role and regulating your sleep (or lack thereof).
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"That's melatonin not melanin. Melatonin regulated sleep."
All sleep-regulated sheep aside, melatonin supplements are cheap and plentiful. The tablets most often come in 3mg size but a doctor said that's "almost certainly too much". Take 1 mg (or 1/2 a 3 mg), about half an hour to an hour before bedtime.
Caution: taking melatonin (especially 3 mg) can cause you to feel groggy in the morning if you haven't gotten a full 8 hours.
Re:Explains a lot (Score:5, Funny)
And a lightin' up a fatty doesn't hurt
--
Man! It stinks in here
Do you make a habit of speaking to your signature?
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It's hard to do without ruining image quality or causing a CRT implosion; but shaving a bit of the glass off the front of the tube might help... They didn't use leaded glass in CRTs just for fun...
Radiation burns are a form of 'tan' right?
Re:Turn the damn brightness down! (Score:5, Interesting)
I find that works.
But.
Almost all my devices will not dim adequately.
Typical dim range is down to 1:128 or so.
1:1000 is much better for use in true dark.
I have to in addition use extra software to increase the dimming, or set dark fonts and backgrounds to get it truly comfortable in a dark room.
This would be a free mod to do in hardware.
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Kpdf can be set to use a black background.
Of course that means installing QT on an otherwise worthwhile system :/
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Almost all my devices will not dim adequately. Typical dim range is down to 1:128 or so. 1:1000 is much better for use in true dark.
Get a phone with an OLED screen (so that black is actually black, no pesky backlight), and a reader that lets you specify arbitrary text color. Set text color to #201000.
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How much of this affect can be conclusively attributed to the light itself and how much of it is actually the adrenaline rush from the video game? I suspect hours reading boring documentation under the exact same light would NOT have even remotely the same effeccts.
It does seem pretty likely that stimulating material on the display has its own effect; but there has been enough messing around with boring light sources(ie. LED arrays in white or blue with no display content at all) to suggest that light itself packs a decent punch.
I suppose, if one wanted to be especially sure, a bit of research on subjects given the stiffest doses of beta blockers that the IRB will allow might be in order. If you crater the beta receptors, this 'adrenaline rush' phenomenon will not be