Circadian lighting plays an important role in healthy workspaces—exposing the human body to wavelengths that support its biological clock. Consistent circadian rhythms directly impact sleep quality, and who doesn’t want their workforce starting the day rested?
But between the complexity of the science and differing ways to quantify the value proposition, several misconceptions about circadian lighting persist. This piece tackles the five most common points of confusion.
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1) Circadian lighting is just a fad.
If you’ve ever experienced jet lag or a sluggish mood on a cloudy day, you know the powerful effects of light. Circadian rhythms are as essential as breathing. The process controls physical, mental, endocrine and behavioral responses, right down to basic functions such as digestion and body temperature.
“Circadian systems are so fundamental that even single-cell creatures possess them. The challenge for humans is that we often have little to no access to daylight in an office setting. Healthy lighting is as critical as diet and exercise—it’s time for the built environment to intentionally support that,” argued Dr. Mark Rea, professor of population health science and policy with the Icahn School of Medicine at Mount Sinai.
Because the circadian cycle runs roughly 24 hours, its effects extend beyond work hours but then boomerang back the next morning. The purpose of circadian lighting isn’t merely to encourage focus during the day—it should also help the body transition to its evening sequence. This is when low lighting and darkness signal the pineal gland to produce melatonin, which induces sleepiness. Humans depend on a timely rise and fall of our sleep hormone.
“Many people accept that there are pillars of wellness such as nutrition, sleep, exercise and mental health. But those pillars need a foundation, and that’s the circadian system,” said Regina Lausell, lighting designer and CEO of Light Vitality Group. “You may not think that drifting 15 minutes from your circadian cycle is a big deal, but doing that over a week adds up. We absolutely carry how alert or groggy we feel into our work day.”
2) There’s only one way to achieve circadian lighting.
It can be challenging to wade through marketing claims for circadian lighting products. Be cautious of wellwashing, the greenwashing equivalent for health benefits. Circadian solutions shouldn’t rest on a single attribute, such as color tunable or white light.
“Our circadian system is quite simple—it needs bright days and dim nights. The core problem is too many employees aren’t positioned near windows and are stuck under low overhead lighting,” clarified Rea. “Something as simple as a task lamp with comfortable horizontal illuminance can start to counteract that.”
This is a shift in lighting design, which typically defaults to horizontal illumination. But the sun is only directly overhead for a small portion of the day. Ceiling light doesn’t reflect the incremental path of the sun’s arc.
“Circadian lighting is all about layers. You aren’t going to achieve the right effect with the ceiling alone—in fact, you might increase glare and energy consumption,” cautioned Dr. Mariana Figueiro, professor of population health science and policy with the Icahn School of Medicine at Mount Sinai. “Amplify the amount of natural light instead and then supplement as needed with architectural fixtures.”
[Related: Daylighting Tips and Strategies for Existing Buildings]
3) The effect is instantaneous.
Even in spaces with optimal circadian lighting, occupants won’t notice spontaneous energy leaps. It’s the same reason that dimming lights after sundown doesn’t cause immediate slumber. The circadian system responds to light at certain intervals, especially in the two-hour window before bed and the one-hour period before rising.
“In a light wellness system, spectral light would fluctuate throughout the day. It would support the continuation of the wake-up cycle as well as moving toward the sleep phase,” Lausell explained. “It takes several hours for the body to suppress or release melatonin. The goal with workplace lighting should be to work with, not against, this natural flow.”
4) It’s costly to implement.
Does circadian lighting sound like it will inflate your project budget? While bulbs, fixtures, sensors and controls can increase expenses, they may not be necessary for every single room.
“Don’t think of circadian lighting as a whole building solution. You can create nested environments within your footprint,” Lausell advised. “Programming should drive where to implement circadian solutions. There might be a handful of areas that truly benefit, such as a team located in the building core or a subterranean level.”
“Remember, daylight is free. Rearrange your layout so as many people as possible are near windows. A simple switch like turning desks so they face windows has benefits,” Figueiro recommended. “Circadian lighting might even be a behavioral change, such as encouraging employees to work outside. Choice matters too, such as permitting people to rotate where they work so they can be near windows for a portion of their day.”
5) The ROI is based on productivity.
There’s a temptation to expect that circadian lighting will impact productivity. But consider how slippery that definition is. What does a productive employee look like and how would you know if their performance improved? Output can hinge on many factors that are difficult to measure: concentration, memory recall, fatigue perception, mood, creativity and morale.
Even if you could pinpoint the exact definition, efficiency varies widely within a single organization. For example, the performance of an IT professional is entirely different than an executive.
“Try shifting the emphasis to sleep. We all need good sleep no matter our job title,” Figueiro stressed. “Furthermore, we can concretely measure what good rest is. We also know that sleep quality can affect conditions such as diabetes, Alzheimer's, cardiovascular disease, depression and anxiety. Circadian lighting is one way to support good sleep habits, which in turn promote a healthier workforce.”
About the Author:
Jennie Morton has been covering the built environment for the past 11 years.
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