Slashdot Mirror
Colors Help Set Body's Internal Clock
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.'”
as a control.
Just in case some slashdotter hasn't hear of it yet:
The people between the very awesome F.Lux 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.
I'll just leave this here:
http://science.slashdot.org/co...
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.
This is widely known, in fact I use a small app in Android that filters the blue color in the screen after noon,
f.lux does a similar thing on Windows PCs, in case anyone was interested.
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 and sunset at 5:00 PM. If you're subject to SAD, then F.Lux won't help with that.
(But, granted, it does feel good on the eyes when it kicks in.)
Part of the problem with light therapy is that it doesn't always work, or only works a little, or doesn't work for everyone. As a scientific result, this fairly shouts "not the complete explanation", so I've played around with this a bit to see what's really happening.
I'm convinced that "length of day" plays a big part in our internal clocks, and things like heavy blue video has an effect. For example, "The Daily Show with Jon Stewart" has a lot of blue and is shown late at night. Watch it with red sunglasses and see if you feel more tired/ready to sleep after watching.
In terms of scientific discoveries, I think there's some low-hanging fruit here. Straightforward hyotheses and studies could be done which would completely characterize the issue, and would point to simple, inexpensive, and drug-free cures to a handful of issues.