Originally Posted by meeera
Or it might not, really. The oft-quoted research showing that tablet use at night-time disrupted melatonin production showed that you needed to use an LCD tablet, no night mode, on full brightness (!!!) for two full hours before there was any disruption. Even at that rather massive level of light exposure, one hour didn't disrupt things.
The current LED-lit ereaders put out a whole lot less light (using sensible settings) at a far less blue level than these experimental conditions used. I suspect that our concerns should be more aesthetic than health-based.
I would tend to agree with the second paragraph, but I disagree with the first one. Having said that bear in mind that blue lightwave is a particular culprit in melatonin suppression, it's precisely what's used in s.a.d. boxes.
To go back to why I disagree with the first paragraph. I don't recall reading anywhere about full brightness having been used specifically, and I also don't agree with the assessment that two hours, or an hour and a half is a lot of time one uses a tablet. Also bear in mind two things:
a. The suppression of melatonin was very significant, akin to what a lightbox might have produced.
b. The subjects were healthy volunteers. This is very important. I tend to have sleep problems, and I am aware by now I have some sensitivity to how I modulate my circadian rhythms. I am convinced that if people with sleep sensitivities had been tested in the study instead, the results would be considerably more pronounced in terms of time required to achieve the suppressing effects and these effects would be even more pronounced. And sleep disorders affect a very high percentage of the population.
So the take home message, shouldn't really be, oh, that's just another study exaggerating something for effect, it should rather be don't use your tablets near bedtime, unless you are a model for good sleep habits and sleep quality.
We simply have not evolved to have bright light emitted to our faces before bedtime. The most our ancestors could do would be a small fire to cook something up. But here most of us are going to bed with mini suns shinning on our faces. We are tricking our biochemistry into a lot of trouble this way.
(Now may I please finally have a mirasol/liquavista/pixel qi/whatever non light emmiting notebook to post on instead of sitting in front of the computer and messing up my body clock?)
Originally Posted by Katsunami
I'm one of those people that has a horrible life because I sleep best from 4am to 11am, while the current world doesn't really give me the chance to do so. (No, it's not "getting used to sleeping from 23:00 to 6:00, because that's what I've been doing for many years, during my work week.) I rarely really sleep except in weekends. The best I can do is slumber. (Not really sleeping, but yet not awake anymore. Somewhere in between...)
It's Sunday now, 1:35 AM. I'll go to bed in about 1,5 hours. Then I'll read for another hour, on a Kindle. When I put the Kindle away, I'll sleep until 10-11 AM (It's still Sunday then, of course.) My Sunday will be great, as was my Saturday.
And monday, hell starts again. (edit: Not to mention, that my Sunday will be short because of going to bed at 23:00, where my Friday is always very, very long.) The usage of computers, tablets, or reading of books before going to bed, or refraining from these things, does not make any difference.
Lol, my brother from another mother!
Though I 've never managed a 23:00 to 6.00 am workweek. At best I can wake up at 9.30 am having gone to bed between 3.00 to 4.00 am.
And I do find that computers and tablets, unlike books/kindles exacerbate this, to occasionally hitting the 6 am time frame as opposed to the 3.30-4.30 am one.