Impact of Light on Human Health and Welfare

Modern life has created a multitude of advantages that were not possible for a pre-industrialized nation.  Yet with all its comforts and technological advancements, none has had a more profound effect upon humans as our simulated environments with sources of light.

During the 1960s and 1970s, a forward thinking professor from Kent State University, John Flynn hypothesized the psychological effects of artificial light on humans.  In Flynn’s research, he proposed resolutions to improve the quality of light for our “spatial Illumination.” 

As research continued into the study of light upon humans, notable ailments have been attributed to the lack of natural light.  Seasonal Affective Disorder (SAD) is common in humans who live in climates where prolong periods of daylight is absent.  A notable difference in depression, as well as a deficiency of vitamin D is linked with the lack of exposure to daylight.  This same effect is identified in shift workers, whose exposure to natural light is limited. 

In 2001 ganglion, a new eye cell receptor was identified as a sensor to slight changing patterns of light upon humans by signaling the nervous system.  This response signals the human brains with changes to the body’s circadian rhythms.  The resulting effect causes an impact upon our emotional state of mind as well as our vital organs, and immune systems. 

A serious impact to our cardiac system invokes changes in patterns of heart rate variability (HRV).  These variations in heart rate can increase our stress levels and ultimately shorten our life expectancies.

Continued research is needed to fully understand the effects the absences of natural light has upon the human body, but enough evidence has concluded that we as designers must recognized the impact of light on human health and welfare when we analyze our building lighting systems.