# LED lighting can "wreak havoc with the internal body clock of nocturnal animals." I am skeptical. **URL:** \ **Category:** Factual Questions\ **Created:** [June 15, 2018, 12:01pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142 "2018-06-15T12:01:32Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [June 15, 2018, 12:01pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/1 "2018-06-15T12:01:32Z")
This claim is made in a [new study](http://www.dailymail.co.uk/sciencetech/article-5835023/Modern-LEDs-cities-affecting-animals-midday-sun.html) by a researcher at the University of Southern California. And it is purportedly because “LED bulbs produce a sharp and intense light.” Huh? Incandescent and gas discharge lamps produce an intense light across a wide frequency spectrum, which obviously includes the frequencies produced by LED lights. So is there anything to this? ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [June 15, 2018, 12:55pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/2 "2018-06-15T12:55:46Z")
Notice that the photo of the light cluster in the story is NOT LED. That right there makes me not trust the rest of the information. Plus, Daily Mail. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 15, 2018, 1:02pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/3 "2018-06-15T13:02:34Z")
_Any_ artificial lighting can mess with the internal clocks of animals. Was the researcher comparing LED lights to other lights, or just to no light at all? ---
**Author:** ![spifflog](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@spifflog](https://boards.straightdope.com/u/spifflog)\ **Post date:** [June 15, 2018, 1:05pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/4 "2018-06-15T13:05:01Z")
I can believe it. There have been several studies that how that using your cell phone right before you go to be causes sleep issues. My wife and I stopped using our phones and hour before we went to be and it’s help us a lot. For millions of years with the sun went down it got dark. Not any more and that’s a rapid change from now. > [@GaryM](#): > > Notice that the photo of the light cluster in the story is NOT LED. That right there makes me not trust the rest of the information. > Plus, Daily Mail. The editor for the story went and found a picture for the story. And the Daily Mail had nothing to do with the study. Red herrings both. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [June 15, 2018, 1:06pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/5 "2018-06-15T13:06:58Z")
Many of these so-called “studies” are dubious at best. The pressure on universities to be awarded grant money on a continuing basis often results in studies that are too brief and include too small a sampling to be valid. Sometimes, as it appears to be in this case, that pressure results in outright incompetence. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 15, 2018, 1:36pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/6 "2018-06-15T13:36:16Z")
Here’s the abstract of the actual study, unless Longcore is on a publishing spree. It doesn’t say LEDs are bad, it says different types of lamps have different levels of effect and LEDs can be tuned to minimize the impact: [https://onlinelibrary.wiley.com/doi/abs/10.1002/jez.2184](https://onlinelibrary.wiley.com/doi/abs/10.1002/jez.2184) > [@](#): > > For many decades, the spectral composition of lighting was determined by the type of lamp, which also influenced potential effects of outdoor lights on species and ecosystems. Light‐emitting diode (LED) lamps have dramatically increased the range of spectral profiles of light that is economically viable for outdoor lighting. Because of the array of choices, it is necessary to develop methods to predict the effects of different spectral profiles without conducting field studies, especially because older lighting systems are being replaced rapidly. We describe an approach to predict responses of exemplar organisms and groups to lamps of different spectral output by calculating an index based on action spectra from behavioral or visual characteristics of organisms and lamp spectral irradiance. We calculate relative response indices for a range of lamp types and light sources and develop an index that identifies lamps that minimize predicted effects as measured by ecological, physiological, and astronomical indices. Using these assessment metrics, filtered yellow‐green and amber LEDs are predicted to have lower effects on wildlife than high pressure sodium lamps, while blue‐rich lighting (e.g., K ≥ 2200) would have greater effects. The approach can be updated with new information about behavioral or visual responses of organisms and used to test new lighting products based on spectrum. Together with control of intensity, direction, and duration, the approach can be used to predict and then minimize the adverse effects of lighting and can be tailored to individual species or taxonomic groups. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 15, 2018, 1:40pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/7 "2018-06-15T13:40:47Z")
> [@Jasmine](#): > > Many of these so-called “studies” are dubious at best. The pressure on universities to be awarded grant money on a continuing basis often results in studies that are too brief and include too small a sampling to be valid. Sometimes, as it appears to be in this case, that pressure results in outright incompetence. This is a thoroughly uninformed and nonsense post. Sure, there are bad studies out there, but your explanation of why makes no sense and you are judging a study on one single newspaper in a tabloid known for inaccuracy and stupidity. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 15, 2018, 1:43pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/8 "2018-06-15T13:43:22Z")
And just in case someone didn’t know, yes there is ample evidence that light pollution is a problem for a lot of organisms. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [June 15, 2018, 2:00pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/9 "2018-06-15T14:00:44Z")
> [@Jasmine](#): > > Many of these so-called “studies” are dubious at best. The pressure on universities to be awarded grant money on a continuing basis often results in studies that are too brief and include too small a sampling to be valid. The greater problem\* is university flacks who craft p.r. releases that are not justified on the basis of study results, and news media that breathlessly cite press releases without bothering to have their content analyzed by experts in the field. \*I am not referring to this particular study. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [June 15, 2018, 2:53pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/10 "2018-06-15T14:53:02Z")
> [@naita](#): > > And just in case someone didn’t know, yes there is ample evidence that light pollution is a problem for a lot of organisms. I don’t think anyone is doubting that. The article that **Crafter\_Man** linked to claims that LED lighting is significantly worse than other types of lighting. It’s the focus on LEDs as being significantly worse that seems a bit questionable. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 15, 2018, 3:13pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/11 "2018-06-15T15:13:45Z")
I don’t have access to the paper, but I found [this article about the paper](https://travislongcore.net/2018/06/12/new-paper-picking-spectrum-to-reduce-adverse-effects-of-lights-on-wildlife/) that shows a couple of key plots from the paper. It’s basically saying the higher the color temperature, the bigger impact it has on wildlife. Most of the lamps they tested are LED, but they include one metal-halide lamp (the really bright white lamps often used in outdoor illumination - stadiums, etc - and some large indoor buildings), and it’s as bad as some white LEDs. Low pressure sodium lamps (the yellow streetlamps) scored best. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 15, 2018, 3:19pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/12 "2018-06-15T15:19:04Z")
By the way, white LED bulbs do have a significant blue component that doesn’t exist in fluorescent and halide lamps - [see here](https://electronics.stackexchange.com/questions/125500/cool-white-led-bulbs-are-they-full-spectrum) for example, see the peak at 450 nm? That’s because the actual LED emits at that wavelength, and some of that lamp is converted by a phosphor into red & yellow light, which balances out the light and makes it look white. This may be why white LEDs have a greater impact than other “white” light sources. If you wear strong eyeglasses, you can often see this - find a small LED lamp (e.g. penlight), and turn your head so you’re looking at the LED through the edge of the eyeglasses where the lens curvature is greatest. With an incandescent bulb, the chromatic aberration of the lens turns it into a smear. But with an LED, it splits it into a blue dot and a red/yellow smear. ---
**Author:** ![John\_Bredin](https://avatars.discourse-cdn.com/v4/letter/j/96bed5/32.png) [@John\_Bredin](https://boards.straightdope.com/u/John_Bredin)\ **Post date:** [June 15, 2018, 3:26pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/13 "2018-06-15T15:26:01Z")
> [@scr4](#): > > Low pressure sodium lamps (the yellow streetlamps) scored best. The sickly yellow streetlamps people have been bitching about for years? :dubious: ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 15, 2018, 3:29pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/14 "2018-06-15T15:29:20Z")
> [@John\_Bredin](#): > > The sickly yellow streetlamps people have been bitching about for years? :dubious: This is a rating of impact on wildlife. Yellow light has the least impact, bluish white light has the most impact. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [June 15, 2018, 3:31pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/15 "2018-06-15T15:31:50Z")
Blue shifted light seems to be well known for this issue in people, even Apple a option to ’ redshift’ the phone during sleepy time hours to help. Seems like yes it would also apply to animals. It is partly for this reason that I do like to get the warm colors when choosing illumination. Another issue I have heard is that some LED’s well the driver produces a high frequency sound. Too high for humans to hear but it was mentioned that some animals, particularly pets can and it can be annoying or even maddening to them. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 15, 2018, 3:47pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/16 "2018-06-15T15:47:23Z")
> [@engineer\_comp\_geek](#): > > I don’t think anyone is doubting that. The article that **Crafter\_Man** linked to claims that LED lighting is significantly worse than other types of lighting. It’s the focus on LEDs as being significantly worse that seems a bit questionable. I think when one discusses science based on an article in “The Mail Online”, making assumptions that people won’t doubt well known scientific knowledge is overly optimistic. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [June 15, 2018, 3:49pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/17 "2018-06-15T15:49:24Z")
> [@naita](#): > > This is a thoroughly uninformed and nonsense post. [\*\*How reliable are scientific studies? \*\*](https://www.kqed.org/forum/201405020900/how-reliable-are-scientific-studies) > [@](#): > > In response to growing concern over flawed research practices, Stanford University has created a new center dedicated to studying and improving the process of research itself. We’ll talk about the most common scientific shortcomings, proposed solutions and how to judge whether research is reliable. ---
**Author:** ![andros](https://avatars.discourse-cdn.com/v4/letter/a/e480ec/32.png) [@andros](https://boards.straightdope.com/u/andros)\ **Post date:** [June 15, 2018, 3:57pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/18 "2018-06-15T15:57:38Z")
Sure. But I think what people are taking issue with might be the following: > [@Jasmine](#): > > …Sometimes, as it appears to be in this case, that pressure results in outright incompetence. On what do you base that assertion? . ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 15, 2018, 4:00pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/19 "2018-06-15T16:00:08Z")
> [@Jasmine](#): > > [\*\*How reliable are scientific studies? \*\*](https://www.kqed.org/forum/201405020900/how-reliable-are-scientific-studies) I didn’t say there were no bad studies. The text on that page you linked to says “We’ll talk about the most common scientific shortcomings, proposed solutions and how to judge whether research is reliable.” I’m not watching the video to get the details, but I would be surprised if “getting grants” is the one and only cause they suggest for publishing of low quality study. And I’d be even more surprised if they suggested “only read the writeup in the tabloids, avoid the actual study” as a method to judge reliability. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [June 15, 2018, 4:52pm UTC](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142/20 "2018-06-15T16:52:13Z")
> [@John\_Bredin](#): > > The sickly yellow streetlamps people have been bitching about for years? :dubious: those are high-pressure sodium IIRC, assuming you mean the pinkish-orange ones. I think low-pressure sodium lamps are plain yellow. [Next page](https://boards.straightdope.com/t/led-lighting-can-wreak-havoc-with-the-internal-body-clock-of-nocturnal-animals-i-am-skeptical/816142.md?page=2)