Have you ever had trouble falling asleep at 2am after binge watching the latest season of House of Cards? Ever pulled an all-nighter then felt strangely awake and alert after walking outside into broad daylight? Ever spent all day at the beach only to sleep like a moss-covered boulder later that night? It probably comes as no surprise that light has significant effects on the human body. In fact, light and health researcher Talieh Ghane is convinced that human biology is the next big thing in lighting design, technology, and policy.
The Visual System and the Biological System
Basically, scientists discovered a group of photoreceptors in the eye called intrinsically photosensitive Retinal Ganglion Cells (ipRGCs for short) that have less to do with what we see and everything to do with the body’s physiological response to light. These cells are dedicated to communicating important signals to the body, like when to go to sleep and when to wake up—our 24 hour body clock. Our circadian system, in turn, controls important bodily processes like hormone production, digestion, melatonin secretion, muscle strength, the rest-activity cycle, core body temperature, immune response, and more.
And while the visual system “responds to light in a fraction of a second,” the biological system is cumulative in nature and takes into account a diversity of factors such as the timing, color temperature, and intensity of the light, plus a person’s history of light exposure and their age—among other things. We do know that exposure to blue light has profound effects on human health and the circadian system. There is more energy in the cooler or bluish part of the color temperature spectrum (think high intensity daylight) versus the warmer or reddish part (think candlelight or campfires).
Humans evolved to respond to high levels of blue light during the day, and virtually no blue light at night. However, with most of us spending the majority of our time indoors during daylight hours and the advent of artificial lighting— not to mention the high level of blue light emitted by electronic devices like cell phones and smart TVs—the body doesn’t know how to respond:
Our body is confused because it doesn’t know when it’s day and when it’s night. During the day we don’t get that much of the intense light that you’re supposed to get if you’re in nature. And at night when you’re not supposed to get any blue light, you get a lot of blue light.
Researchers have linked unhealthy amounts of blue light at night and the disruption of the circadian system to an increase in cancer rates, infertility problems, retinal degeneration disease, and diabetes.
Ideally, humans would be exposed to the dynamic range and intensity of light in the great outdoors, like our Netflix-less ancestors. But even though that’s rarely possible in this day and age of lighting fixtures and constant facebooking, we can still embrace healthy lighting habits in our day-to-day lives.
Ghane offers seven tips for health lighting for those of us who are not lumberjacks or carnies.
7 Tips for Healthy Lighting
1. The first and most important: Try to get at least one to two hours of high intensity blue light during the day (ideally two hours after you wake up). This helps to reset your circadian system. It can even help you “cheat”—if you work high intensity light into your daytime schedule, you will be less sensitive to blue light later in the day when you’re trying to get in some quality screen time right before bed. Not that you should do that or anything.
A few simple changes in your day-to-day life can make all the difference. For a more in-depth take on lighting and health, you can check out the full interview here.
David Hakimi is a lighting specialist and one of the co-founders of Alcon Lighting. A graduate of the University of California Los Angeles (UCLA), David works on the front lines of the energy-efficient lighting revolution, enabling architects, designers, and lighting engineers to transition from outmoded halogen and fluorescent lighting to what David calls “the ideal replacement for all lighting applications,” —LEDs. David takes particular pride in Alcon’s design, energy, and green building knowledge, tracing his and Alcon’s commitment to quality, innovation, accountability and value back to the lessons learned from his father, a Southern California lighting salesman and consultant for more than two decades. Passionate about reducing climate change and protecting the environment, David has been particularly valuable in ensuring that his clients and customers comply with rapidly-evolving green building codes. You can connect with David on LinkedIn at https://www.linkedin.com/in/david-p-hakimi/.
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The Chicago Department of Buildings recently announced that energy design requirements for building projects in Chicago have been updated as part of the city’s multi-phase code modernization process. For permit applications started on or after June 1, 2019, the Chicago Energy Conservation Code (Title 14N of the Municipal Code), based on the 2018 edition of the International Energy Conservation Code, published by International Code Council, Inc., will now apply.
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Talieh Ghane researches the interaction between light and health at the California Lighting Technology Center. We talked about the biological vs. visual system of light, how to synchronize your circadian clock for better health, how light is like a drug, and why you shouldn’t be on your phone right before bed (guilty).
Our relation to light as humans is complex. Though many of the effects of light on our biology are still unknown, there are several we know and understand. Light also plays a major role in regulating human biological responses, including our internal body clock or circadian rhythm.