I made f.lux, and this is something I study a lot.
This study was done on rodents, and the problem with the reporting of it is that rats are >100x more sensitive to this kind of light than humans are.
For white light, below about 5-10 lux, it is very hard to measure melatonin suppression in humans. This study finds that rats have significant melatonin suppression at 0.1 lux, which has been known since 1974 (Minneman et al) at least.
Still, don't sleep with the TV on, and don't see bright (room) light within a couple hours before bed, because that will actually suppress total melatonin by a significant percentage.
> Still, don't sleep with the TV on, and don't see bright (room) light within a couple hours before bed, because that will actually suppress total melatonin by a significant percentage.
How do you avoid seeing bright light in the last few hours before bed?
Thank you for making f.lux, by the way. It's very cool, and I hope it gets more thorough biomed testing soon.
Turn off the TV, get something like F.lux on your mobile/tablet or don't use it and if you need light get something with low-blue output.
I searched for a long time to find a room light that avoided blue light and you have options with dimmer stands and certain bulbs. I ended up with some absurd-looking salt lamp that casts a soft orange light and has a dimmer (and allegedly releases magical ions that purify or clean the air -- not buying this last one).
Yeah, I know that. Specifically bright blue lights. I wondered what people did to avoid blue light in the few hours before they went to bed. Turns out dim, orange lamps are one answer.
>Production of melatonin by the pineal gland is inhibited by light to the retina and permitted by darkness. Its onset each evening is called the dim-light melatonin onset (DLMO).
It is principally blue light, around 460 to 480 nm, that suppresses melatonin, proportional to the light intensity and length of exposure. Until recent history, humans in temperate climates were exposed to few hours of (blue) daylight in the winter; their fires gave predominantly yellow light. The incandescent light bulb widely used in the twentieth century produced relatively little blue light. Wearing glasses that block blue light in the hours before bedtime may decrease melatonin loss. Kayumov et al. showed that light containing only wavelengths greater than 530 nm does not suppress melatonin in bright-light conditions. Use of blue-blocking goggles the last hours before bedtime has also been advised for people who need to adjust to an earlier bedtime, as melatonin promotes sleepiness.
When used several hours before sleep according to the phase response curve for melatonin in humans, small amounts (0.3 mg) of melatonin shift the circadian clock earlier, thus promoting earlier sleep onset and morning awakening.
So this might explain why I started sleeping better when I installed f.lux[1] which starts eliminating blue light from your screen as soon as the sun sets.
debian/ubuntu users can `apt-get install redshift`. you can add it to your ~/.xsession if you're a luddite like me, or find some other way to make sure it's always running when X is running.
Install dimmers! And use warm-dimming bulbs like incandescent/halogen (or some newer LEDs). The combination of lower brightness and a light that actually dims to 2000K will measurably wipe out the stimulus. Most other kinds of lighting will not.
All white lights produce "some" blue light. As the other comment mentioned, the white point/color temperature indicates how much. I'm a fan of lights with adjustable color temperature, such as the Philips Hue bulbs. I use ~5000K-6500K when working, then fade down to dimmer light at ~2500K in the evenings. I use a Kinect for this, rather than the Hue app.
Probably a matter of "light temperature". Low temperatures of 2500-2700 K (aka "warm white") are reddish, while high temperatures around 3000 K (aka "daylight" [ETA: in advertising parlance]) are bluish. Go to a well-stocked hardware store and they may have a display demonstrating the differences.
I have Gunnars that I wear at home. The advantage is you're not limited in use when compared to flux. You can get them in prescription as well, however they're already fairly expensive.
Gunnars do a great job at blocking UV and some kinds of glare, but they mostly don't block the light around 480nm, so they can't block all alerting light.
You want glasses that look orange (not pale yellow), like the $7 Uvex ones.
The cheapest option is to wear orange glasses like the $7 Uvex S1933X. Room light is a big stimulus (especially if you don't have dimmers), and they're a lot easier to use than screen films. We measured the spectral response here: https://twitter.com/JustGetFlux/status/398599984334909440
Look at above comment about f.lux. You don't even need hardware; you can do it with software. But a quick search for such filters already delivers a lot of results: http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3D....
Just choosing one of those results randomly (http://www.amazon.com/Green-Onions-Supply-Anti-Fingerprint-P...) seems to address that light spectrum specifically: "They reduce blue light from your screen by 38% over the most harmful portions of the visible light spectrum (380 to 500 nm)"
The question posed here and especially the parent's comment about night light causing cancer cannot rely on the publication as hypothetical basis. The article merely states that the lack of melatonin conflicts with the effectiveness of the drug tamoxifen.
So now they relied on a lack of light to increase melatonin levels, but did they have a control group who simply were fed/injected with melatonin? Because if there is a difference between that group, then it becomes even more interesting: what else does the body do in these circumstances of total darkness?
Of course, in general we need better sleep hygiene than what we do to ourselves now, and darkness at night would be one way. But for many it's not easy to just switch to a regime like that.
tamoxifen caused a dramatic regression of tumors in animals with either high nighttime levels of melatonin during complete darkness or those receiving melatonin supplementation during dim light at night exposure.
I wonder what else we're disrupting with high levels of light. My crappy ass landlord but a giant fucking light right outside my bedroom. The problem is if I have blackout blinds to keep it dark at night, I won't wake up in the morning.
My crappy ass landlord but a giant fucking light...
OMG these "security lights" are horrible! I love walking around the countryside at night, but you have to be careful where you look if you don't want to be completely blind the whole time. It seems like everyone in the country has to have this giant 200W halogen bonfire burning all night. So many nights I've been tempted to have a bit of fun with the rifle. "Oh did I wake you up? I guess a turn-about is fair play."
If I had any pull with the PUC I would stop that "un-metered" crap before I stopped Ameren from raising rates to pay for a new reactor. (Because why should our investors have to actually make an investment?) The whole "security" aspect of these lights seems like baloney anyway. If that's the purpose, why not get a reflector and point the damn things down at the ground?
They are very convenient when working outside at night. They also increase security because there is no cover of darkness. If anything is out there you can easily see it.
I walk outside at night all the time and it's nice to have it and certainly not blinding. Especially if you are more than a few dozen feet away from it. And no one has any good reason to be out there at night anyway.
Cities and towns are way worse offenders in this. Hundreds of lights at much higher intensities. Even parking lots and empty buildings get illuminated like its day time. It creates enough light pollution to block out the stars even. And it's payed for by taxpayers.
Unless you're working outside all night, please install a light switch. I find a simple headlamp is more convenient when I have to see small details, and it's not pointing at my eye so I retain some night vision.
The idea that lighting contributes to security is questionable. Well-lit areas are easier to observe and navigate without calling attention to oneself. If it's your yard and you've lived there more than a month you should be able to walk around it blind-folded. Potential miscreants don't have that home-field advantage, and they appreciate your leaving the lights on. While they're out there you won't see them because you're inside watching TV. However if it were dark and they were shining flashlights or vehicle headlights around you might notice that. I'll allow that if there is an actual guard on attentive duty all night, lighting will be helpful.
I know that lights make you feel more secure, but that's just a reason to have them on while you're awake.
When you're walking outside at night "all the time", even though you don't have "any good reason to", you probably only see the ground in front of your feet. With all that artificial light, there's no way you're seeing any wildlife that isn't standing in the road, more than a few dozen stars, the landscape, etc.
Cities could certainly pollute less with light. Also, those who like bright outdoor lights on all night should move there.
Save your taxpayer angst for some other issue. The reason these lights exist is that power is really cheap when few people are using any power, which is generally true from bedtime to daylight. Of course the power company could be overcharging in any particular situation, but they wouldn't have popularized "security lights" in the first place if they hadn't had a bunch of generating capacity to dump.
I keep meaning to try them and never getting around to it.
I did look into automating the drapes, ideally with a small electric motor on a timer. It seems like something you should be able to do for $200 or so, but I couldn't find gear that would actually just list the price...
I'm afraid that may be a low estimate. I thought the same and was shocked at what prices I could find. I ran into the same problem of finding prices, too.
I would be very cautious in extrapolating these results to humans. Animal are known to have different circadian rhythm processes. Also, cancer xenographs (human tissue in animals) don't exactly have a great track record in terms of generating new cancer drugs.
Melatonin is inhibited by light reaching the eyes. An eye mask might be enough. Speaking with regard to sleep, not cancer, I have to block any LEDs on things like battery chargers to sleep well. I despise the trend of putting blue power indicators on things used at night (I'm looking at you, Air-O-Swiss).
So do I, the blue LED is the curse of the modern era. Old time red led's have zero annoyance for me but when I walk through the living room at night and it's all alight in blue glow from the dvr etc it annoys me on a visceral level.
Thick black electrical tape is the best fix unfortunately.
> I despise the trend of putting blue power indicators
Blue indicators should be deemed illegal. I had a laptop that had no less than 14 (fourteen) blue light sources on it. I had to unscrew the part and remove the LEDs.
> however, during the 12 hour dark phase, animals were exposed to extremely dim light at night (melatonin levels are suppressed), roughly equivalent to faint light coming under a door."
If a faint light from under a door is able tu suppress melatonin, does this mean utilities such as f.lux are completely useless?
I though the same thing. Anyone who's ever been camping with no other light source other than a full moon will remember how much light (I guess is it's pretty blueish?) the moon puts out.
But, maybe it's not too much, since our eyes are probably very night-adapted when there's no other light source?
>If a faint light from under a door is able tu suppress melatonin, does this mean utilities such as f.lux are completely useless?
I found f.lux only a little helpful -- it wasn't until I added blackout curtains and started wearing blue-blocking glasses at night around the house that I noticed a strong effect.
That does seem amazingly sensitive, but still -- if faint light from under the door (partially?) suppresses melatonin, I would imagine that a 27" monitor would do so significantly more.
I have sleep problems and sometimes I take melatonin (4gr) at night 30 mins before bed. It is a harmless supplement and is easy to find and buy online or in farmacies... it works wonders
4g or 4mg? Natural amount of secreted melatonin is much less (< 1mg), you're overdosing with 4mg. I use 0.3mg Herbatonin, which is bioidentical natural form of melatonin from a plant. 10-20mg is therapeutic dose.
I find it interesting that over-the-counter melatonin comes in pills ranging from 0.25mg up to 10mg - a 40X range.
I suspect some people just try whatever bottle they grab first, and may find either no effect, or unwanted effects (excess grogginess/nightmares), and never try another dose.
Sorry... typo, 4mg obviously. I know is "slightly" overdose (1mg/day is the recommendation here in the EU), but as I said I take it every now and then, because of stress and jetlag.
The whole "bioidentical hormones" thing some describe as unscientific, but I've been taking 10mg synthetic without knowing I've overdosing (that was the most popular OTC dose) with no effect. 0.3mg Herbatonin works pretty quickly. Here's something I just found: http://www.naturalhi.com/media/custom/Newsletter%20Melatonin...
I can see the headline now: "Scientists Say Darkness Cures Cancer"...
EDIT: Apparently, the fact that I'm mocking the kind of "science reporting" that would turn this result into that headline wasn't screamingly obvious. I'm surprised; it's a phenomenon I've seen discussed often enough here.
This study was done on rodents, and the problem with the reporting of it is that rats are >100x more sensitive to this kind of light than humans are.
For white light, below about 5-10 lux, it is very hard to measure melatonin suppression in humans. This study finds that rats have significant melatonin suppression at 0.1 lux, which has been known since 1974 (Minneman et al) at least.
Still, don't sleep with the TV on, and don't see bright (room) light within a couple hours before bed, because that will actually suppress total melatonin by a significant percentage.