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Science

Colors Help Set Body's Internal Clock 52

First time accepted submitter MakeItGlow writes A new study by researchers from the University of Manchester found that mice use the color of light to set their body clock. The researchers investigated whether color signals from the eyes wound up in the suprachiasmatic nucleus—the part of the brain in vertebrates that keeps time using electrical and chemical signals. From the article: "Scientists have long known about the role light plays in governing circadian rhythms, which synchronize life’s ebb and flow with the 24-hour day. But they weren’t sure how different properties of light, such as color and brightness, contributed to winding up that clock. 'As a sort of common sense notion people have assumed that the clock somehow measures the amount of light in the outside world,' says Tim Brown, a neuroscientist at the University of Manchester in the United Kingdom and an author of the new study. 'Our idea was that it might be doing something more sophisticated than that.'”
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Colors Help Set Body's Internal Clock

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  • by turkeydance ( 1266624 ) on Monday April 20, 2015 @02:05PM (#49512689)
    as a control.
    • by bondsbw ( 888959 )

      Even if particular colors activate signals in our internal clocks, it's possible that color-blind people adapt to it. It's also possible that color-blindness generally does not target the colors that play an active role.

    • the subject line and the comment proper.

      You're not Horatio Crane, you seven-digit cretin.

    • Probably won't work since the rods overlap on the colors they can receive, which is why the colorblind mix up the colors.
      The red rods will pick up certain shades of blue, as will the green rods.

      The blue light, unless a very deep blue, will then activate all three types of rods.

      http://www.colourblindawareness.org/colour-blindness/types-of-colour-blindness/

  • by schweini ( 607711 ) on Monday April 20, 2015 @02:11PM (#49512773)
    Just in case some slashdotter hasn't hear of it yet:
    The people between the very awesome F.Lux [justgetflux.com] software have been saying this for quite a while, so their great little software adjusts your monitor's color temperature after sunset, and before dawn, to be 'warmer'. Their logic being that the blue components of white light are just unnatural to stare at at night, and mess up our biorythms.
    All sounds a bit esoteric, but I challenge everybody to use F.Lux for a week or so (until you're used to it), and then disable it at e.g. 2am.
    Your eyes will bleed, and you wont understand how people can stare into a super bright white square (the monitor) for hours on end at night.
    • by slaughts ( 50394 )

      Along these same lines, I use CF.lumen on my Android phone. I does the same thing, making the display warmer at night. Much easier on the eyes.

    • I've used F.Lux and it does everything it says. It's a polite program, I've got no problem with it per-se, but I removed it from my system.

      For one, the sunset transition happens in a couple of seconds, and it's quite noticeable. The speed isn't a problem, nor is the "noticing", but I think a slower sunset might be more effective.

      The bigger issue was "length of day". F.Lux synchronizes to the local length of day (based on your latitude and the current date), so in the winter you're still seeing short days an

      • Re: (Score:3, Informative)

        Actually both of those issues are easily fixed! The transition can be changed to 60 minutes instead of a few seconds, and the length of day can be adjusted by giving it a different set of geographic coordinates. I use both of those tricks to customize it. :-)

    • I'm not certain whether using f.lux really improves my sleep (although I'm certainly not complaining if it does). What it does do is make my desktop look more like an object in the room. When a white area on the screen has the same color a white piece of paper would have in the same light that essentially makes using a computer more... immersive. It just feels more natural if the monitor forgoes accurate absolute color representation in favor of more accurate color representation within the context of local
    • The concept of sun light being the trigger for sleep/wakeup has been around for centuries but it wasn't an important subject of conversation until recently (I say this because sleep disorders have become a major issue in our society). What this study does it goes further into the inner workings of the brain. We have observed human behavior to light but in depth research has never been done (citation required). This is where this research comes into play. If they can properly map the impact of light on the h

    • by Trogre ( 513942 )

      I second this. Personally I use Redshift [jonls.dk] to accomplish the same thing on my PCs, and the simpler Nightfilter [google.com] on Android (although the latter doesn't automatically adjust based on your latitude and time of day).

      The difference between "night" and day mode is, well, night and day. When I turn if off late at night my eyeballs scream and then heave a sigh of relief when I re-engage it.

      • by Trogre ( 513942 )

        although the latter doesn't automatically adjust based on your latitude and time of day

        That should read:
        although the latter doesn't automatically adjust based on your latitude, longitude, and time of day

  • by Okian Warrior ( 537106 ) on Monday April 20, 2015 @02:23PM (#49512889) Homepage Journal

    I'll just leave this here:

    http://science.slashdot.org/co... [slashdot.org]

    Noontime clear-sky sun measures 9500, blue light through office window with indirect daylight is 250, a desk lamp measures 45, and an LCD TV up close measures 7 uW/cm^2 in the frequency range of the retinal ganglia (480 nm) which is thought to be the part of the eye that senses daily cycles. (Mammalian Eye [wikipedia.org] on Wikipedia.)

    So far as I can tell laptops and related devices don't generate an appreciable amount of energy in this range, it's more the artificial indoor lighting.

    As an experiment, I've started wearing red-tinted wrap-around sun glasses 2 hours before bedtime. I can still work, read, watch TV and all that, but the glasses mask off the blue frequencies, telling the brain that the sun has gone down.

    It had an almost immediate effect. I'm a long-time sufferer of insomnia who has tried everything, but wearing the glasses fixed the problem in the first week.

    I'm also a lot more "peppy" during the day, and I wonder if long term exposure to late-night artificial lighting (and low level during the day) is a cause of depression. Depression meds take about 6 weeks to have an effect, so I'm guessing that it would take about 6 weeks for the glasses to have an anti-depressive effect as well. I'm on week 3 with the glasses.

    • by Anonymous Coward on Monday April 20, 2015 @02:27PM (#49512947)

      It had an almost immediate effect. I'm a long-time sufferer of insomnia who has tried everything, but wearing the glasses fixed the problem in the first week.

      Well you would think that, but you're looking at the world through rose-tinted glasses.

    • Depression meds take about 6 weeks to have an effect, so I'm guessing that it would take about 6 weeks for the glasses to have an anti-depressive effect as well. I'm on week 3 with the glasses.

      That has to be rather large glass of water.

    • What glasses do you use? Have a link?
    • by Prune ( 557140 )
      Your experiment fails to account for the influence of another well-known effect, which is that perceived color temperature is affected by absolute light intensity. Indoor lighting is almost always orders of magnitude weaker than sunlight, and this is why using lighting matched to actual noon color temperature will look far too blue. This is why advanced light bulbs as used in museums and so on that specifically approximate a sun+sky spectrum (to result in proper color reproduction) are available centered at
    • by Sark666 ( 756464 )

      To back this further, see the episode the nature of things called lights out!

      One I interesting bit they noticed nurses working night shifts had a higher rate of breast cancer. This was suspected to be related to their prolonged elevated melatonin due to too long light exposure. Their solution was to give them glasses filtering out blue light while working.

      www.cbc.ca/natureofthings/episodes/lights-out

  • What do think about lights that adapt during the day? Such as: The Sunn Light https://www.kickstarter.com/pr... [kickstarter.com] Lumious https://www.indiegogo.com/proj... [indiegogo.com]
  • As a result of research like this, I created SunsetScreen [skytopia.com] to allow the user to change the screen's colour filter to *any* colour, not just a hue along the colour temperature scale. An orange tint is probably good at night for increased melatonin production, but a blue tint may be desirable during the day to increase seratonin.

    I also prefer using it to Flux because you can set the exact time of sunset/sunrise instead of letting the seasons dictate it (4pm sunset in the winter? - thanks but I want the scre
    • by Tomster ( 5075 )

      This looks great, I have similar complaints about Flux. One question, which I didn't see answered in the documentation: Does your app handle multiple monitors?

      • by Twinbee ( 767046 )
        'Fraid not as yet. If I get enough requests (I've had one so far), then I may implement it.
        • by Tomster ( 5075 )

          Yeah that would be great... at the moment my main display says "soothing nighttime" while my laptop screen shouts "midday sun" :). Multiple monitors is becoming more common, and your app fits pretty well with the power user demographic that's likely to have 2+ displays.

          If this feature doesn't scratch an itch for you, perhaps you could try funding it via something like GoFundMe for a little extra in your pocket. Just a thought. Regardless, thanks for the time you've put into it, I'm going to try it for a wee

          • by Twinbee ( 767046 )
            In a way I hope giant 30"-40"+ UHD screens become common so that we can split the screen when needed, or view it as one other times. I have a 32" TV as a monitor and it's great.

            Problem with 2+ monitors is that I can't easily test for it, so I won't know if I have it working or not.
            • by Tomster ( 5075 )

              Nice -- I'd love to have a big UHD TV for development. I started with a Commodore 64 and a TV. 320 x 200 resolution.

              Have a look at http://virtualmonitor.github.i... [github.io] or http://superuser.com/questions... [superuser.com] (search for "windows virtual display driver") if you decide to work on the multi-monitor feature.

              • by Twinbee ( 767046 )
                Thanks. I've asked on Stackoverflow [stackoverflow.com], so maybe someone will reply. Hey, I'll even chuck in a bounty if no one replies.

                If someone replies, I'll give you the honour of testing to see if it works! ;) I presume you've tried and it won't currently work.

                Yes I had a C64 too. I remember with the Amiga 500 thinking 640*512 was a really high res, and 1280*1024 was ridiculously large. Now it's painfully blocky. Mind, most screens are bigger these days, so that can bias one a bit I guess ;)
              • by Twinbee ( 767046 )
                Oh I've had a repsonse from Stackoverflow asking:

                Does it do nothing on a machine with two monitors or does it throw an error? Does it only change a single screen? What is the user experience?

                From one of your earlier posts, I presume it just does nothing with the second screen (no error message or anything right?)

  • Colors are really just spectral bands, UV and IR are just bands beyond human perception (caveat: not all humans, some can see a bit into the UV range).

    In short, if you have things like SAD, increasing the spectra which penetrate in the morning (remember in the dawn the light goes through a large swath of atmosphere, not the small amount at noon) and adding those 1-2 hours before increases your internal body temperature in a manner similar to waking up due to daylight.

    Yes, this works through eyelids (mostly

The amount of time between slipping on the peel and landing on the pavement is precisely 1 bananosecond.

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