iarc blog

Lighting and Human Health

 

            The articles, Influence of Architectural Lighting on Health, from InformeDesign’s newsletter, and In Eyes, a Clock Calibrated by Wavelengths of Light, in The New York Times, give great insight into the ways human health is affected by lighting conditions. These articles discuss ways in which human health and welfare are greatly impacted by the lighting conditions to which we are exposed. As artificial lighting technology has changed and continues to change, we experience different lighting conditions and different benefits and consequences from those lighting conditions. Current benefits include overall convenience, ability to complete tasks after dark, and an increase in overall societal productivity. The consequences are not completely understood, although there is significant scientific evidence regarding the relationship between human health and well-being and lighting conditions. Continued research must be done to know the exact effects of lighting on humans, especially as lighting technology changes and we are exposed to new conditions.

            As suggested in the articles, circadian rhythm is greatly affected by artificial light, but the effects vary depending on the color of the light wave. Evidence suggests that blue light waves inhibit the production of melatonin, a hormone that is released in the body to promote sleep, for a greater length of time than red light waves. Additionally, experimental evidence suggests that blue light waves make users feel more alert and focused. This may explain why it is easier to fall asleep after reading a book in bed, as opposed to watching TV or reading on an e-reader.

            Decreased levels of melatonin affect our ability to fall asleep, in turn affecting our circadian rhythm from resetting our bodies’ functions. Interruptions in our natural circadian rhythm have a wide range and, potentially, long-lasting impact on our overall health. It is, therefore, evident that artificial lighting has the potential to negatively affect human health based on the type and exposure to it, by interfering with our circadian rhythm.

            Natural light also impacts our health and well-being. In geographic locations where days are shorter or rainier weather is experienced, there is a high incidence of Seasonal Affective Disorder (SAD). SAD is a condition that causes seasonal episodes of depression in its sufferers. A typical treatment of SAD is light therapy, a treatment in which patients are exposed to bright light at determined intervals.

            Based on existing and ongoing research on the effects of light, both natural and artificial, on human health, it is critical for architects and designers create spaces in which full benefits of lighting can be maximized while the consequences can be minimized or alleviated. For instance, blue light waves can be used in areas that require a high degree of alertness and focus provided that there are spaces available that allow the brain and body to relax and maintain a natural circadian rhythm.