# Do LEDs Disrupt our Biological Clocks?



## Vox Clamatis in Deserto (Oct 30, 2011)

Is this just one of the usual 'everything electrical is bad for you' articles that are a staple of modern 'save the planet' journalism? Or is there something worth investigating?

Many light boxes that folks use in northern climes to treat Seasonal Affective Disorder are LED based these days from what I can see.

Will we be told by the 'experts' to bring back incandescent lights because they are more 'natural'?



> Do LEDs Disrupt our Biological Clocks?
> 
> By BEN P. STEIN, Inside Science News Service
> Oct. 30, 2011
> ...



The full article is here: http://abcnews.go.com/Technology/da...white-light-emitting-diodes/story?id=14838491


----------



## jtr1962 (Oct 30, 2011)

The author ignores one very important fact-namely that the natural starlight which our ancestors have been exposed to from day one is heavy in blue light, and yet somehow that hasn't affected melotonin or sleep cycles. It might be more of issue of quantity of light rather than the spectrum. High levels of artificial light may disrupt sleep cycles _of some people_, while others will be unaffected. Even assuming the studies were valid (and a 3 to 8 percent suppression of melotonin isn't necessarily statistically significant), the conclusions of some involved in the studies are bizarre to say the least: _Haim and his co-authors call for a "total ban of the outdoor emission of light at wavelengths shorter than 540 nm" -- and to go back to older low-pressure sodium lamp designs -- "to reduce the effects of decreased melatonin production and circadian rhythm disruption in humans and animals."_. These conclusions completely ignore the reasons LPS lamps are being phased out in favor of metal halide and/or LED. LPS (and also HPS) lamps were never really acceptable for outdoor lighting precisely because their spectrum results in poor color rendering, poor seeing, and in general casts a depressing, unnatural yellow pallor on the night. They're also unsafe for roadway lighting because they kill peripheral vision. The best solution, assuming someone is particularly affected by outdoor lighting with blue in the spectrum, is to pull their blinds down and light their residence with whatever type of light suits them.


----------



## blasterman (Oct 30, 2011)

I would have never thought that high pressure sodium lamps had a lobbiest group, but if they do, the author is clearly being bought off because the science here is so bad nobody can take it seriously.

Let's first exclude the arguement for dark skies around observatories. This is an entirely exclusive issue and has nothing to do with melatonin production or anything else. Observatories need surrounding cities to either turn their parking lot lights off, direct them down, or use narrow band spectrum light sources like low pressure sodium so it can be filtered out. I've no issues with this other than to point out white LEDs are no more offenders than mercury vapor or halide. Actually, the LED sources are the LEAST offenders because their light cones are the most distinct and they are far better at directing their light downward than metal discharge bulbs. In short, Im totally supportive of regulations specifying narrow bandwidth light sources within a proximity of observatories.

The melatonin arguements are flat out stupid. What melatonin production has been proven to be affected by short wavelength light sources requires far higher lux levels than a parking lot at night or freeway. Most adults have been proven to be deficient in melatonin due to simple age and hormone issues, and the stuff is dirt cheap at the drug store.

High pressure sodium doesn't bother me for driving as much as it does jtr1962, mainly because I find low CRI, high CCT LED lamps to be just as distracting. If I had a vote on the issue I'd clearly put my weight behind any regulation dictating that roadways be lit with 4100-5000k lamps with a minimum 75CRI. That would be a quantum leap over HPS.

If you're otherwise worried about melatonin affecting your sleep maybe you shouldn't be drinking beer at a hockey game at 9pm anyways. I'm guessing most people wanting to get to sleep aren't sitting in a parking lot staring at the lights, so the authors conclusions are too baffling to be taken seriously.


----------



## Vox Clamatis in Deserto (Oct 30, 2011)

> I would have never thought that high pressure sodium lamps had a lobbiest group, but if they do, the author is clearly being bought off because the science here is so bad nobody can take it seriously.



I agree, this does appear to be an advocacy hit piece on LED's in favor of sodium lights.

I've been flying around Europe at night recently, those sodium lights seem to be very popular in places like Spain, France and Holland. The author appears to be a legitimate science writer associated with the American Institute of Physics. Perhaps he's just trying to promote a friend's research or something but raising the issue of dark skies in the same breath as circadian rhythyms and melatonin production also seems a little desperate to me.


----------



## PhotonWrangler (Oct 30, 2011)

The other problem with the "blue rich" claim is that we've had mercury vapor streetlights and yard lights around for decades, and these are heavily rich in blue. In fact they cast a color that's not too far off the mark from moonlight, neither of which seems to have been causing mankind any problems. If they're serious about banning "blue rich" LED lights, they need to ban mercury vapor lights also. Oh, and moonlight.


----------



## MichaelW (Oct 30, 2011)

I have a healthy disdain for cool-white LEDs as any normal person does, but if they want to help with the 'melatonin problem', then it is about time for the water fluoridation hoax to end.
That practice does terrible long-term damage to the pineal gland, and has no benefits to teeth.

ABC 'news' was pretty lax with the spectral power distribution graphs, lets see a 3000K warm-white vs. a 4000K neutral & 5000K cool. {I think this is why they are called presstitutes in some locales}


----------



## Vox Clamatis in Deserto (Oct 30, 2011)

Some of this Ben P. Stein article may derive from an earlier news item that blue LED's may be bad for you:

http://texyt.com/bright+blue+leds+annoyance+health+risks

It has the same melatonin, LED, cancer link that today's article has. Seems a little fishy to me...


----------



## idleprocess (Oct 31, 2011)

I can think of numerous factors that disrupt my circadian rhythm before I can start to finger the LED lighting I've installed. It's such a low level effect when compared to everything else such as...

Caffeine
Household pets
My neighbor's excitable beagles
Airplanes flying overhead (I'm near a large airport)
Traffic in my neighborhood
The availability of entertainment and/or _something_ to do 24/7 (ala the internet, cable TV)
A lack of a consistent sleep schedule
My occasionally variable work schedule (usually 08:00 - 17:00, but sometimes I have to start at 04:00)
The occasionally noisy climate controls for my house
The lack of a totally dark environment in my bedroom

I would need to address the above variables before addressing the likes of the warm LED bulbs I have on my desk in my office (consciously indistinguishable from an incandescent) and in the kitchen, the neutral LED strip lighting I fabricated in my bedroom (which is typically lighting up the room before I go to bed), and the neutral LED lamp on the nightstand. It's worth noting that I had more or less the same sleep patterns before I moved into this house with the various LED lights.

Doing shift work for years on end _(second shift/15:00-0:00 for nearly four years with a six-month stretch of third shift/22:00-07:00)_ and my caffeine consumption has probably extracted a far greater and more lasting toll than whatever subtlety is associated with excess blue light sources.


----------



## CKOD (Oct 31, 2011)

So basically, herp derp, cool white isnt as relaxing to be in as warm white. 

I think most people would agree that a room lite with 2700-3500k light would be easier to relax in then one lit with 5000-6000k light, regardless of source.


----------



## PhotonWrangler (Oct 31, 2011)

Vox Clamatis in Deserto said:


> Some of this Ben P. Stein article may derive from an earlier news item...



Wait a minute. _Ben Stein?_

Bueller?

Bueller?

I'm sure it's a different Ben Stein.


----------



## Vox Clamatis in Deserto (Oct 31, 2011)

> I'm sure it's a different Ben Stein.



I was thinking exactly the same thing. The other guy's middle initial is J.

See: http://www.imdb.com/name/nm0825401/


----------



## SemiMan (Oct 31, 2011)

Hey I love LEDs, but you have to be sticking your head in the sand if you don't believe that their spectrum impacts melatonin/serotonin more than HPS or Tungsten. It does and it happens at mesoptic levels .... just do a bit of research.

Realistically, with a well designed outdoor lighting system, the light levels should drop off very quick outside the target lighting area and with modern lighting, sky glow is far less of a problem.

Indoors, yes it can be an issue. One of the reasons you find it so easy to stay awake on the laptop is the light from the screen (amongst other things).

So better to address than be in denial. 

Semiman


----------



## idleprocess (Oct 31, 2011)

SemiMan said:


> Hey I love LEDs, but you have to be sticking your head in the sand if you don't believe that their spectrum impacts melatonin/serotonin more than HPS or Tungsten. It does and it happens at mesoptic levels .... just do a bit of research.
> 
> Realistically, with a well designed outdoor lighting system, the light levels should drop off very quick outside the target lighting area and with modern lighting, sky glow is far less of a problem.
> 
> ...


Based on those figures in the article, it would seem that LCD backlights are a considerably worse problem indoors than LED lighting.

Bring back CRT's?


----------



## SemiMan (Oct 31, 2011)

idleprocess said:


> Based on those figures in the article, it would seem that LCD backlights are a considerably worse problem indoors than LED lighting.
> 
> Bring back CRT's?


 

I will pass on the CRT and potentially no advantage anyway as a white CRT has lots of blue.

In general I run black on white as it is the easiest for the brain to process (no really it is).

However, at night, if just text, I will run reverse colors at times ... white text on black. It can be soothing almost.

Semiman


----------



## carrot (Oct 31, 2011)

Two of my friends are absolutely convinced that color temp has a distinct effect on their sleep cycles. They both use F.lux (as do I) to change the color temp of their computer monitors throughout the day and wear yellow/orange sunglasses at night a few hours before they go to bed, as well as use warm white LEDs. For one of my friends it has been more successful: he now no longer needs an alarm clock to wake up in the mornings, and reports his quality of sleep has improved. 

I do notice it takes me less time to fall asleep when using F.lux on my computer than not. YMMV.


----------



## idleprocess (Oct 31, 2011)

Hey, let's meander off topic a bit...



SemiMan said:


> I will pass on the CRT and potentially no advantage anyway as a white CRT has lots of blue.
> 
> In general I run black on white as it is the easiest for the brain to process (no really it is).
> 
> ...



I did CAD for several years and found the default setup of black lines on a white background maddening - so much _something_ (background) bleeding into a little bit of _nothing_ (the lines I needed to see). I quickly switched to black background and had an easier time of it. It works well for CAD, but not always so great for text, which most people have trained themselves to read so fast that the visible edge gradients are distracting.

Of course, this was back when I had a nice 19" CRT at my workstation. Lovely screen, but like all CRT's it was a bit hazy. With the generally superior sharpness of LCD's, it might not make as much of a difference anymore, but I changed careers and industries right as LCD's became more or less universal.


----------



## yifu (Nov 2, 2011)

Highly doubt it. However Cree's eye safety evaluation here http://www.cree.com/products/pdf/XLamp_EyeSafety.pdf does show that all current Cree LEDs have a spike in the 400-450nm blue spectrum but the white LEDs emitt very little in the 450-480nm royal blue spectrum, which is more dangerous to the eyes.


----------



## jtr1962 (Nov 4, 2011)

blasterman said:


> High pressure sodium doesn't bother me for driving as much as it does jtr1962, mainly because I find low CRI, high CCT LED lamps to be just as distracting. If I had a vote on the issue I'd clearly put my weight behind any regulation dictating that roadways be lit with 4100-5000k lamps with a minimum 75CRI. That would be a quantum leap over HPS.


I'll gladly get behind such a requirement myself. I never quite understood why 62 CRI is considered "acceptable" for outdoor lighting. Especially with LEDs, it appears the efficiency you gain going from 75 CRI down to 62 CRI is marginal at best, yet the 62 CRI just looks horrible compared to 75 or 80 CRI. Sure, we don't need sunlight-perfect color rendering to light roads, but I tend to think safety/depth perception would be better by requiring at least 75 CRI, better yet 80. The efficiency penalty of a better CRI spec, based on what I've seen, appears to be practically nil, probably not much over 5%.


----------



## robertdayton (Jan 11, 2012)

LolOLLOLOL @ blue LEDs cause cancer


----------



## SemiMan (Jan 11, 2012)

jtr1962 said:


> I'll gladly get behind such a requirement myself. I never quite understood why 62 CRI is considered "acceptable" for outdoor lighting. Especially with LEDs, it appears the efficiency you gain going from 75 CRI down to 62 CRI is marginal at best, yet the 62 CRI just looks horrible compared to 75 or 80 CRI. Sure, we don't need sunlight-perfect color rendering to light roads, but I tend to think safety/depth perception would be better by requiring at least 75 CRI, better yet 80. The efficiency penalty of a better CRI spec, based on what I've seen, appears to be practically nil, probably not much over 5%.



75 may not seem high but it actually is. Guaranteed 75CRI, not typical, will take more than a 5% hit. If you compare CREE XPG Neutral (75 typ) against Outdoor(70typ), then it looks like the Neutral is only providing one BIN higher output, i.e. 7/122 = 6%. However, that is just what product bins they are offering. That is indicative, but not the actual performance hit. The real hit is higher, and hence impacts costs.

High CRI does not guarantee depth perception. Low level 100CRI, low color temp light is not great as your peripheral vision will be poor. I would take cooler, lower CRI to get the depth perception, etc.

People often associate poor CRI and high color temp together. Yes 7000K, 65 CRI can be harsh depending on what is driving the CRI error. However, 65CRI, 4000K is not that harsh.

Semiman


----------



## hank (Jan 11, 2012)

A few years back, when I read about the discovery of the fourth melanopsin receptor -- the one sensitive to blue-green that controls melatonin cycles -- I checked and found our CFLs have that big spike (like all fluorescent lights, and 'white' LEDs use a fluorescent layer too). I sent several different lamps to Craig at LEDMuseum, because he has a spectrum analyzer, and picked several that don't emit or filter out the blue-green, that we have been using after 8pm. We sleep a lot better.

YMMV (your melatonin may vary) -- if you're young-to-middle-aged, you've got a robust sleep cycle, hard to disrupt.
If you've got a baby in the house, or someone past the mid-50s, those folks are more sensitive to disrupted sleep cycles.

The science is there to read: http://scholar.google.com/scholar?q=melatonin+wavelength+sleep
and in particular from this university source: 
http://scholar.google.com/scholar?hl=en&q=rensselaer+lighting+sleep+wavelength

There's a huge marketing/PR push by LED suppliers to deny this.
It'll really impact sales if it's accepted too soon.
In a couple of years, the industry expects to have LED lamps out that can filter the blue-green.
Several companies have announced they'll have those on the market -- but not just yet.
Once supply is in the pipeline, this issue will be revived, because they'll have something to sell to replace the current lamps.

Gotta clear out inventory _before_ admitting a problem could exist, though.
That's how it works.

Meanwhile, you can figure out how to get amber LEDs or "bug light" filtered CFLs if you want to try it yourself.

------
Aside -- the pharmaceutical companies love sleep disruption, because they sell pills for that. 
It's a huge market. www.somnusthera.com/insomnia.asp
"... of the 40-70 million American adults who suffer insomnia (of which 25 million are chronic or severe cases), only 20% take prescription sleep aids. ..." Marketing is a complicated world.


----------

