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from the the-blues-may-be-good-for-you dept.
Submitted via IRC for chromas
Not such a bright idea: why your phone's 'night mode' may be keeping you awake
"Night mode" is one of those features you may be aware of only because your phone keeps telling you about it. At some point while you are lying in bed at night sending texts, your screen may politely suggest you activate a function that shifts the colours of your screen from the colder to the warmer end of the spectrum. It is supposed to help you sleep better.
Findings in a study led by Dr Tim Brown and published in Current Biology suggest this is the very opposite of correct. The research, carried out on mice, appears to rubbish the notion that blue light disrupts sleep. All things being equal, warm yellow light is worse.
[...] According to the study, brightness levels are more important than colour when it comes to stimulating the body clock. However, when the light is equally dim, blue is more relaxing than yellow.
This makes basic sense: daylight is yellow, twilight is blue, and sunrise and sunset are pretty reliable ways to tell your body clock what time it is. Of course, at this point, we only know it works on mice – and mice don't have phones. "We think there is good reason to believe it's also true in humans," says Dr Brown.
(Score: 5, Informative) by SunTzuWarmaster on Thursday December 19 2019, @01:06PM (3 children)
So - it took me a while to find the article (summary links to another summary links to the university links to the journal, not published in current issue, etc.). It is here:
https://www.cell.com/current-biology/fulltext/S0960-9822(19)31368-5 [cell.com]
And titled (would it kill any of these summaries to mention the title?!) - Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight
• Cone-derived blue:yellow color signals influence circadian entrainment in mice
• The blue colors associated with twilight suppress circadian light responses
• Color signals support circadian entrainment to low-amplitude light:dark cycles
• Color signals buffer the clock against cloud-related changes in light levels
Also - I'm pretty sure that the *actual* article concludes EXACTLY THE OPPOSITE of what the summary claims. From the article:
"Contrary to common beliefs, it is yellow rather than blue colors that have the strongest effect on the mammalian circadian system. This relationship aligns with natural shifts in the color of ambient illumination, detectable during twilight by mammals with di- and tri-chromatic visual systems [12]. Accordingly, we show that this color signal supports robust and stable circadian-driven behavior in the natural world, where stochastic variations in light levels introduce ambiguity to intensity as a signal of time of day."
This would suggest that an increase in yellow (during the day) and a decrease of yellow (during the night) would provide the strongest response. My Android phone has a "black and white" night mode that satisfies these constraints nicely. The study indicates that "less yellow" is better than "less blue", and that the blue effect is generally smaller. Also note that the mice used in the study are nocturnal (like most mice), so you have to reverse all the effects. Further note that the authors reference that increased melatonin (spending time in sunlight) has a significantly more powerful effect.
So yea - [time in the sun] is better than [yellow suppression] is better than [blue suppression]. Hardly a "night mode is keeping you awake" headline - especially if your night mode suppresses both blue and yellow (Android black/white mode, by default).
PS - having submitted articles before - I do not blame the submitters or editors here - this was kind of a lot of homework, and was deliberately misrepresented (or misunderstood) from multiple summaries.
(Score: 0) by Anonymous Coward on Thursday December 19 2019, @01:59PM
I think the other benefit of the B&W mode on Android is it is a simple way of saying, "PUT THE DAMN PHONE AWAY!"
(Score: 2) by All Your Lawn Are Belong To Us on Thursday December 19 2019, @02:12PM
Well, the two issues I would note are: a) Prima facie, mice are not humans. They do discuss this in the article and believe it may apply to humans, and the argument seems cogent. But still mice are not humans. b) The article actually discusses a couple of different scenarios with different testing. The answer, however, is in the study summary you linked to. They state that while yellow-shifted colors may naturally assume to ecologically signal twilight, as sun angle drops there is actually a blue-shift to the light. Thus blue light may actually trip the circadian reset - which correlates with the biological observations they represent in the study. They note that blue light produces weaker circadian response. That's what you want if you're using lights at night - you don't want the body tripped into thinking it's suddenly daytime and you don't want the body responding in circadian rhythm to lights at night. And I think (though would appreciate correction if I'm wrong) that when they're talking circadian entrainment and alignment they are talking about recognizing when it is night / sleepy time.
In short, I think the summaries are mostly correct. The study suggests blue light, per se, isn't necessarily bad, because what you don't want is a circadian response to artificial light ("Hey, it's daytime!")
This sig for rent.
(Score: 0) by Anonymous Coward on Thursday December 19 2019, @07:38PM
uhm. "black and white mode"? the light is still red + green + blue. same amount of blue as red and green.