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Fantastic article and thank you for sharing such a comprehensive look into the application of circadian supportive lighting.
While it is true that ZGF is leading the charge with circadian lighting applications, it must be pointed out that both the Swedish Ballard and the Children’s Hospital of Philadelphia projects occurred during my tenure at ZGF. I am responsible for design work and all the challenges associated with shepherding the innovative lighting systems for these fine projects. Mr. Brennan did support the commissioning effort on Swedish Ballard but did not participate in the Philadelphia project. The mentioned software was also co-developed by myself and Mehlika Inanici at the University of Washington.
Rob, please see this article related to color & intensity study done at RPI. It seems like both are likely important.
Wow! What a great read! My grandfather recently passed away after two years in a nursing home. He was in the dementia ward due to the stroke leaving him with very limited communication abilities, but most of the residents were actual dementia patients. A lot of yelling, aimless wandering, occasional violent tendencies, as described in this article. I wish they had this lighting system for my grandfather and the other residents. It sounds like it makes the dementia ward a little less hellish.
Good, balanced article that was like a ride on a see-saw. “this is so great”…followed by…”well, maybe it wasn’t the lighting alone”. Kids and adults alike are easily interested in dynamic things, like quickly changing a light color. I, for one, remain convinced that this is mainly psychological, not physical. At the very end of the article the most important fact is revealed: It is not color temperature, although certain wavelengths have a greater affect; not duration, although that is very important…it is INTENSITY of the light exposure which would have definitive affects on your internal clock. Keep the research going! It may lead to some really great suff. For now: Smoke, mirrors and marketing…for the most part. Just like Apple and their night shift: proven wrong…it is all about the intensity, not the color.
This article was very informative. I am looking forward to seeing how the new findings will effect our current view on lighting levels. The Children’s Hospital of Philadelphia Behavioral Health Unit referenced in the piece is a great example of the use of circadian lighting to improve the overall mood of patients and instill a more positive environment. ZGF Architects were the designers behind the project (https://www.zgf.com/project/childrens-hospital-of-philadelphia-medical-behavioral-unit/) and are regularly utilizing circadian lighting in their recent designs.
Great article, thanks for helping to raise awareness of the link between light and health! Another approach worth mentioning, there are several companies devoted to recreating natural light indoors (providing sunlight during the day, then candle or fire light at night). Telelumen has pioneered the ‘recording and playback’ of natural light: http://www.telelumen.com/. Sunlight Inside has developed stand-alone lamps which automatically reproduce the cycles of natural light: http://www.sunlightinside.com/. These companies actively mix light from multiple different color LEDs to mimic the daily, and seasonal cycles of natural light. You can benefit from light that’s closer to the natural light cycle today, while the scientists continue to work on the underlying mechanisms, so why wait!?
Living in Alaska, there was a pronounced difference of wakefulness, energy and mood; depending on the season. Five hours of rest in June seemed much more refreshing than ten hours in December. I attributed this to the day-length at the time and always figured that it’s possible to increase the total amount of one’s wakeful hours by using auxiliary lighting to simulate an earlier sunrise, for instance. Or swap northern and Southern Hemispheres at the equinoxes if you’re well-to-do. So I’m very interested to procure tunable LEDs.
I have some experience with optoelectronics and tried like heck a few years ago to design an LED lamp that would mimic the solar profile but was unable to find enough examples (colors) to completely cover the bandwidth from red to violet. Most lamps I found were narrow BW (like 15nm) and/or narrow viewing angle, so this left many gaps. Plus some colors cost much more than others. So I’m going to find out about these tunable guys! I enjoyed reading all of your thoughtful comments.
Excellent article on a complex topic. What’s exciting is the growing recognition that changing lighting types as well as intensity can affect sleep, alertness and overall human behavior. We need to better quantify the effects, but so far it seems encouraging. The only thing this article misses is the flip side of the picture — the widespread use of fixed-color bluish LEDs in the outdoor environment with very little investigation of the impact on wildlife or humans. Sadly, the only metrics usually considered for outdoor lighting are cost and energy efficiency. I have written about those topics for IEEE Spectrum and Optics & Photonics News.
Excellent article. It will be interesting to see how recommended lighting levels will adapt to the new findings.
This is a great article, filled with lots of good stuff. It seems that the more we learn, the less we really know. There’s a broad range of theories out there ranging from blue-rich, to bad blue vs. good blue, to the other problem of Kelvin temp doesn’t tell the story. Even “warm” 2700K produced with phosphor coated blue pump has a blue spike in the theoretical “bad blue” range. Unfortuately, I also saw an article that measured the SPD of iphones nighttime mode and while visually it looks very different ( more amber) the SPD isn’t that dramatically changed.
The great news is that awareness is coming and after 30 years in the lighting fixture industry industry, it’s nice to see LEDs finally discussed in their real advantage rather than how they got hijacked for lpw and efficiency. The future of lighting and what we are going to learn about its effect on human health and well being is going to make the last 2 decades of energy savings look like child’s play.
This is the best article on LED lighting I have read in quite a while. Most articles focus on anecdotal problems with LED lighting and demonstrate only a limited understanding of the lighting revolution that is going on around them.
Great article, excellent detail on the non-visual photoreceptors in the eye. I’m a little surprised that there wasn’t any mention of programs that can change the quantity of blue light emitted by devices that we use all the time, such as f.lux (https://justgetflux.com/) for laptop and desktop computers, or night shift on the iPhone. I’ve been using f.lux for about 10 years now, and it’s really helped me personally go to sleep at earlier and more consistent times. For the DIY enthusiast, there many many Kelvin scale tunable LEDs out there (Phillips white ambiance comes to mind) so you can try implementing these systems at home. That being said, I’d love for my workplace to try this type of lighting.