The Link Between LED Lighting and Observed Health, Learning and Productivity
May 01, 2020
Use of LED lighting is transforming the role that lighting can play in an environment. Some LED lighting technology allows for variation in lighting intensity and color temperature that can help people augment their environment.
LED lighting has become significantly more affordable, too. Since 2008, prices for LED lighting have dropped a remarkable 90 percent and as a result, LED lighting use is exploding[1]. In 2035, LED lighting is expected to represent 84 percent of the market, compared to just 13 percent in 2017[2]
Research has shown that the amount and type of light in your environment can positively or negatively impact your circadian rhythm[3]. According to the National Sleep Foundation, the circadian rhythm is basically a 24-hour internal clock that is runs in your brain’s “background,” cycling between sleepiness and alertness at regular intervals.[4]
When your circadian rhythm and your sleep patterns are not in sync, you can have trouble staying awake and sleeping at appropriate times. Circadian rhythm synchronization challenges can often be found among with non-traditional work schedules. A National Sleep Foundation poll[5] found that only 63 percent of shift workers (versus 89 percent of non-shift workers workers) said that their work schedule allows them to get enough sleep.
LED Lighting
The flexibility that LED lighting offers helps support circadian entrainment, or an impact upon the circadian rhythm, since the timing, intensity, duration and wavelength of light affect the human biological clock[6]. Some LED lighting technology allows adjustments in lighting intensity and Correlated Color Temperature (CCT), and thus, the Spectral Power Density (SPD) changes. CCT measures the relative color appearance of white light, from lower (warm/yellow) to higher (cool/blue) values on the Kelvin (K) scale[7]. SPD is a measure of concentration of light at particular wavelengths.
Combining those variables with adjustments based on time of day has driven use of a new term: human-centric lighting. As more and more research demonstrates, human-centric lighting can be used to optimize the environment in office buildings, schools, hospitals, among many other building types.
Office Lighting Does Matter
Improving workplace lighting can pay off. Installing human-centric lighting featuring a “circadian-friendly” lighting sequence at a property company for example, recorded an employee-perceived increase of productivity by 18 percent[8], according to an article in the Lux Reviewing citing research conducted by The Twente University, the Free University Amsterdam[9].
The study also found that after lighting improved, employees improved their work accuracy by 12 percent, 76 percent of employees described feeling happier, and 50 percent reported that they felt healthier[10].
While it may be tempting to dismiss workplace lighting as insignificant, research shows otherwise. A study conducted by the American Society of Interior Design indicated that 68 percent of employees complain about the lighting situation in their offices.[11]
The time-controlled lighting system implemented at the property company features a circadian rhythm-friendly lighting sequence that varies color temperature and intensity throughout the day. During the morning and early afternoon, high illumination levels and cool indirect white light stimulates employees. Light levels fall and become warmer at mid-day and during late afternoon[12] to aid in the continuation of the circadian rhythm and help the body prepare for melatonin secretion and subsequent sleep.
Just-Right Lighting Can Improve Learning
LED lighting also can be used to help improve the learning environment in classrooms. A 2018 study published in the journal, Optics Express[13], suggests that dynamic lighting can support student classroom learning. In the study, researchers at the Korea Advanced Institute of Science and technology in South Korea found that lighting can be optimized for various activities from test-taking to reading based on correlated color temperatures.[14]
This study[15] found that students felt more alert and scored higher on their tests when they were in a classroom with 6,600 K lighting, a cool, blueish white that mimics natural daylight, when compared with two other kinds of lighting. Comparison lighting included CCTs of 3,500 K (which is a neutral white) and 5,000K CCTs (cool white). These options were compared against a classroom using standard fluorescent lighting, which served as a control group.
An important point is that just as lighting can have a profoundly positive impact on the way people perceive their mood, well-being, and productivity, using the wrong technology, or using it in the wrong way can have a negative impact on the same characteristics. For example, leaving the lighting at 6,600K throughout the day could have adverse effects on the students’ circadian rhythms[16]. The modulation of intensity and color temperature throughout the day, or selecting particular intensities and color temperatures for specific tasks have both proven to be beneficial.
Can Lighting Support the Healing Environment?
Some LED lighting technology may also impact assessments of health and well-being.[17] Research has found that adequate and appropriate exposure to light is critical for health and well-being of patients as well as staff in healthcare settings[18].
LEDs Magazine reports[19] that human centric LED lighting can impact perceptions of well-being at healthcare and senior living facilities. These effects can include positive impacts for people suffering from Alzheimer’s disease and related dementias reducing rates of depression, agitation, and falls.
LED lighting can be used to mimic natural lighting to support patients’ needs[20]. Researchers at the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, New York, report[21] that using special circadian lighting can help hospital patients get a good night’s sleep, and that the benefits of adequate sleep may speed healing and recovery. According to the institute’s director, Mariana Figueiro, PhD, director, we have learned a lot about how light impacts health over the last 15 to 20 years. She reports that humans are designed to be exposed to high amounts of light during the day rather than the constant dim lighting found around-the-clock in most hospitals[22].
Studies of circadian lighting have found that recreating changes in natural light over a 24-hour period can be useful in a various clinical settings.[23]
For example, research suggests that manipulating artificial light could prove a useful non-pharmacological tool to regulate the circadian rhythms of older adults, especially those suffering from dementia[24].
Clinical benefits from this approach have been observed in patients with Alzheimer’s, in those undergoing rehabilitation after acute stroke[25].
The flexibility offered by LED lighting enables adjustment of color correlation and Spectral Power Density, intensity and timing as needed to match various environments. Adjusting these factors can offer a wealth of benefits that can help optimize environments like schools, healthcare and senior facilities, and workplace applications.
[1] 5 Charts That Illustrate the Remarkable LED Lighting Revolution, ThinkProgress web site, Aug. 2, 2016
[2] Adoption of Light-Emitting Diodes I Common Lighting Applications, U.S. Dept. of Energy, Office of Energy Efficiency & Renewable Energy, https://www.energy.gov/sites/prod/files/2017/08/f35/led-adoption-jul2017_0.pdf , 2035 penetration of 86 percent reference on page page 4, 2016 LED penetration on page 9
[3] Blume, Christine, Garbazza, Corrado; Spitschan, Manual, “Effects of light on human circadian rhythms, sleep and mood,” Somnologie, Aug. 20, 2019, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751071/
[4] What is Circadian Rhythm, How Sleep Works, Sleep Routine, Sleep Study, the Science of Sleep, National Sleep Foundation, https://www.sleepfoundation.org/articles/what-circadian-rhythm
[5] Shift Work Disorder, National Sleep Foundation, https://www.sleepfoundation.org/sleep-disorders/shift-work-disorder
[6] Duffy, Jeanne F, MBA, PhD. And Czeisler, PhD, M.D., “Effects of Light on Human Circadian Physiology, Sleep Med Clin, June 4, 2009, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2717723/
[7] Specifying Today’s Products, United States Office of Energy Efficiency & Renewable Energy, , https://www.energy.gov/eere/ssl/specifying-today-s-products
[8] The Growing Case for Human-Centric Workplace Lighting, Memoori, Smart Building Research, nov. 21, 2017
https://memoori.com/growing-case-human-centric-workplace-lighting/
[9] Molony, Ray, “Human Centric office lighting ‘boosts productivity,’” Lux Review, Your Independent Guide to Lighting, 30 October, 2017,
https://www.luxreview.com/2017/10/30/human-centric-office-lighting-boosts-productivity/
[10] Molony, Ray, “Human Centric office lighting ‘boosts productivity,’” Lux Review, Your Independent Guide to Lighting, 30 October, 2017,
https://www.luxreview.com/2017/10/30/human-centric-office-lighting-boosts-productivity/
[11] Molony, Ray, “Human Centric office lighting ‘boosts productivity,’” Lux Review, Your Independent Guide to Lighting, 30 October, 2017,
https://www.luxreview.com/2017/10/30/human-centric-office-lighting-boosts-productivity/
[12] Molony, Ray, “Human Centric office lighting ‘boosts productivity,’” Lux Review, Your Independent Guide to Lighting, 30 October, 2017,
https://www.luxreview.com/2017/10/30/human-centric-office-lighting-boosts-productivity/
[13] Howard, Jacqueline, How Just the Right Lighting May Improve Learning in Classrooms,” Huffpost, April 29, 2016,
shorturl.at/MQVY5
[14] Howard, Jacqueline, How Just the Right Lighting May Improve Learning in Classrooms,” Huffpost, April 29, 2016,
shorturl.at/MQVY5
[15] Choi, Kyungah and Suk, Suk, “Dynamic lighting system for the learning environment: performance of elementary students,” Optics, Express, Vol. 24, Issue, 10, Copyright 2016 Optical Society of America, https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-10-A907
[16] Howard, Jacqueline, How Just the Right Lighting May Improve Learning in Classrooms,” Huffpost, April 29, 2016,
shorturl.at/MQVY5
[18] Joseph, Anjali, PhD., Impact of Light on Outcomes in Healthcare Settings, Published by the Center for Healthcare Design, 2006, https://www.healthdesign.org/chd/research/impact-light-outcomes-healthcare-settings
[19] The Piper senior assisted living facility achieves health benefits with BioStar LED lighting, LEDs Magazine, Aug. 29, 2016, https://www.ledsmagazine.com/specialty-ssl/article/16678709/the-piper-senior-assisted-living-facility-achieves-health-benefits-with-biostar-led-lighting
[20] Shine a Healing Light: Circadian-Based Lighting in Hospitals, MedScape, Feb. 28, 2018, https://www.medscape.com/viewarticle/893225
[21] Shine a Healing Light: Circadian-Based Lighting in Hospitals, MedScape, Feb. 28, 2018, https://www.medscape.com/viewarticle/893225
[22] Shine a Healing Light: Circadian-Based Lighting in Hospitals, MedScape, Feb. 28, 2018, https://www.medscape.com/viewarticle/893225
Science Daily, Rensselar Polytechnic Institute, “Transforming patient health care and well-being through lighting, Feb. 23, 2018, https://www.sciencedaily.com/releases/2018/02/180223092139.htm
[23] Blume, Christine, Garbazza, Corrado; Spitschan, Manual, “Effects of light on human circadian rhythms, sleep and mood,” Somnologie, Aug. 20, 2019, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751071/ (see: Light therapy as an intervention in other medical conditions)
[24] Hanford, Nicholas and Figueiro, Mariana, Light Therapy and Alzheimer’s Disease Related Dementia: Past, Present and Future, Jan. 13, 2013, NCBI, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553247/
[25] Shine a Healing Light: Circadian-Based Lighting in Hospitals, MedScape, Feb. 28, 2018, https://www.medscape.com/viewarticle/893225