Human Centric Lighting Takes LED Lighting to a Higher Level

The human body reacts to sunlight and darkness by releasing hormones that direct our internal clock, known as our circadian system. Recent research demonstrates that building occupants’ circadian rhythms can be disrupted when they spend a great amount of time indoors without access to the Earth’s natural lighting cycle.

Upsetting our internal clock can affect our ability to perform or concentrate, and literally puts us at risk for a lot of diseases. Human Centric Lighting extends the scope of lighting beyond the traditional architectural design approach that focuses on aesthetics, visibility and safety, and considers additional lighting aspects in order to better improve occupant productivity, wellness and health. Human Centric Lighting design objective is to implement systems using a science based approach, considering both visual and non-visual effects of light from a physiological and psychological perspective.

Human Centric Lighting applications are designed to mirror the Earth’s natural lighting cycle. Indoor lights, with more blue components or higher color temperatures, operate during the day to simulate the daytime circadian cycle outdoors. Warm temperature low light levels, with greater amber and red components, are used in the evening to simulate the nighttime part of the circadian cycle. Adjusting the lights helps stimulate people during the day when they need to be sharp and alert. It also assists in relaxing them during the evening as they prepare for a good night’s sleep. With Human Centric Lighting, lights are adjusted for color temperature, brightness or/and color to improve mood and concentration.

Human Circadian Rhythm

The repetitive 24 hour human circadian rhythm is where the concept of Human Centric Lighting came from.

According to The Lighting Research Center at Rensselaer Polytechnic Institute, the world’s leading center for lighting research and education, “biological rhythms that repeat approximately every 24 hours are called circadian rhythms. Light is the main stimulus that helps the circadian clock, and thus circadian rhythms keep a synchronized rhythm with the 24 hour day. Without this synchronization, research has shown that we may experience long-term decrements in physiological function, neurobehavioral performance and sleep, and are put at a higher risk for cardiovascular disease, diabetes and certain forms of cancer.”  

Jet lag is a well explained and commonly experienced form of circadian disruption. We all have felt that non-stop tiredness after flying across multiple time zones. That inability to stay focused and lack of alertness is the result of disrupting our circadian rhythm.

Matching Light Characteristics with Human Circadian Rhythms

Human Centric Lighting systems use LED technology and intelligent lighting control systems to match light characteristics that map to natural human circadian rhythms because we know the effect that daylight has on humans. The intent of these systems is to enhance productivity and performance, as well as address the psychological and physiological problems that are created by disruptions to our circadian clock. While circadian rhythms are built into the human body, they alter to the environment by external cues – these cues are primarily daylight.


Human Centric Lighting is a very attractive environment for the healthcare industry. These smart lighting applications have been found to be good to many types of patients in various healthcare settings.

A report from the National Center for Biotechnology Information explains that critically ill patients in the intensive care unit suffer disproportionately from sleep deprivation and frequent sleep disturbances. The brain trauma ward at Aarhus University Hospital in Denmark implemented a Human Centric Lighting system to address patient sleep issues in the hope that it would help patients recover faster.

Another area in healthcare where Human Centric Lighting is helping make progress is with Alzheimer’s and related dementias (ADRD) patients. This can result in nocturnal wandering, sleep problems and associated daytime irritability. It is common for patients suffering with ADRD to have their circadian rhythms upended because they are spending most of their time inside and therefore not receiving sufficient natural daylight. Studies from the LRC concluded that a light treatment made to increase circadian stimulation during the day can be used to increase quality of life in those with ADRD. Further research at LRC shows that along with improving behavior, sleep and mood in people with ADRD, lighting has the potential to delay the transition of those living at home to more controlled environments.  

Commercial Real Estate

Disturbing or interrupting circadian rhythms can also affect office employees from a productivity and performance perspective. A study by the University of Twente, VU Amsterdam and CBRE Netherlands in 2016 confirmed the connection between people’s health, well-being and ability to perform and their working environment. For this research, a lighting system with a timer on a circadian friendly schedule was installed. Warm light in the morning, strong bright light in the afternoon and dimmed light in the evening were programmed. Participants who were working with the lighting settings perceived their work performance as 18% better overall. 71% of them felt more energized, 78% felt happier and 78% felt healthier. Above all, the outcome of the study showed a 12% increase in task accuracy and 10% improvement in productivity.


Human Centric Lighting systems have also proven to have advantages in educational settings. High school students are reported to have trouble with being alert earlier in the day. Setting levels of light to match daylight has helped with morning alertness in teenagers. For young students, lighting can be tuned to help them settle down for nap times and then adjust for an increase in awareness during classroom testing times and learning periods.