We all know that light can have a profound effect on our mood and on our health. But we’re probably not aware of the many ways that light interacts with and influences our daily lives. Additionally, we may also not be aware of the long history of using light as therapy, or the recent breakthroughs. We probably learned in middle school that our bodies need sunlight in order to synthesize vitamin D. We also know the dangers of too much exposure to the sun. The ultraviolet rays can damage our eyes and lead to skin cancer.
Today, solid-state lighting technology—or LED lighting—offers a combination of energy-efficiency, precision and versatility in lighting that has never been seen before. These advantages are placing LED light sources in the forefront of various fields, including the health industry. The topic “LEDs, Light and Health” is both fascinating and incredibly broad. So, we’ve found it necessary to make this a series of articles.
The History of Using Light as Therapy
Since light has such a powerful effect on us, it’s no surprise that scholars and physicians of the ancient world developed the application of heliotherapy – the use of sunlight exposure – to treat various health conditions. Greek, Roman and Arabian figures in heliotherapy included Herodotus, Galen, Celcus, Cicero and Avicanna. Hippocrates recognized that depression was more common in the winter months in Greece, and he attributed this to the reduction in sunlight exposure.
It wasn’t until the 19th century that the scientific understanding of light as therapy began to advance. In 1806, Pinel identified two types of seasonal depression, one occurring in the winter and another in the summer. This led to Ponza’s work, which demonstrated that light therapy was beneficial for treating patients with mental illness (1). By the 20th century, the concept of circadian rhythms appeared. Philip Hockberger writes:
“The first evidence of biological rhythms originated with the study of plants. In 1729, De Mairan showed that leafs display periodic movements even in complete darkness that corresponded to day-night cycles… The earliest evidence of light-dark cycles in animals was provided by Kiesel in 1894… Between 1926-32, Bremer…. These results and others led Bunning, in 1936, to propose the concept of an endogenous biological clock in animals modulated by daily cycles of light and dark. In 1959, Halberg coined the term “circadian rhythms” to describe these cycles” (1).
Seasonal Affective Disorder (SAD)
Late in the 20th century, a Bell Labs scientist named Herb Kern provided the critical data needed to prompt the National Institute of Health to establish a study of seasonal depression and light (2, 3). The term “Seasonal Affective Disorder”, or SAD, is now familiar to most of us. In simple terms, SAD is a state of depression that results from the reduced exposure to sunlight during the winter months. SAD can make us feel rotten! The symptoms can include depression, loss of motivation, excessive sleep, difficulty concentrating, fatigue, carbohydrate craving and weight gain.
As many as 10 million Americans suffer from SAD, and another 10 to 20 percent have mild symptoms of SAD. Women are more likely to be affected than men, but the severity in affected men can be worse. (4). In the workplace, SAD becomes a significant drag on productivity and will often lead to increased health care costs. Sixty-nine percent of employees—many of whom work in safety-critical industries—are tired at work, according to a recent National Safety Council report (7).
Ordinary levels of indoor light are not sufficient to overcome SAD. However, ‘phototherapy’ with high intensity light has been proven to be very effective (5,6). How remarkable that such a serious disorder is so easily treated—with light!
There is now a large and rapidly growing body of medical and scientific research into the need for light, the effects of light on our mood and health, and the use of high levels of light to prevent seasonal depression. Most adults spend up to 90% of their lives indoors. This puts the focus on determining if the light we provide in our homes and workplaces is really adequate, and if it is correctly ‘tuned’ for the time of day (more on this in a future part to this series). The medical journals are difficult for the layperson to understand, however we can find helpful summary articles online. One example is from Gaby Del Valle who asks the question, “Do SAD lamps actually work?” After her investigation into Light Therapy, Gaby writes:
“I was skeptical that shining a bright light in my face would make me feel better, even though people do it all the time. And even if it did work, I assumed it’d address the symptoms of my winter lethargy without fixing whatever the underlying problem was.
“But light therapy, it turns out, is actually very effective. Katie Sharkey, an associate professor of medicine, psychiatry, and human behavior at Brown University’s Alpert Medical School, told me she often prescribes light therapy to patients diagnosed with SAD.”
Recommended Lighting Levels
At Big Shine Energy, we dedicate ourselves to serving the needs of today’s commercial and industrial workplaces. A key factor in improving the mood, energy, concentration and safety is to install state-of-the-art LED lighting. Our professionals will survey your facility with you complete a lighting audit using our proprietary audit app. Then, we provide you with computer photometric models of the before-and-after results. As an option, we can discuss with you a time-of-day high level of lighting space you set aside for those employees who would like to try increased light exposure at work. As a minimum, you will see the positive effect that meeting IES-recommended lighting levels with crisp, bright LED light has on everyone, and you will be making a positive step for the bottom line and for the environment. Call us today!
(1) Hockberger, Philip E., History of Ultraviolet Photobiology, Northwestern University Feinberg School of Medicine, Chicago;
(2) Lewy, Kern et al., Bright artificial light treatment of a manic-depressive patient with a seasonal mood cycle; Am J Psychiatry 139:11 November 1982, Published Online:1 Apr 2006
(3) Rosenthal Norman E., A patient who changed my practice: Herb Kern, the first light therapy patient; International Journal of Psychiatry in Clinical Practice, Volume 4, 2000 – Issue 4, pp. 339-341.
(4) Seasonal Affective Disorder, Psychology Today
(5) Ciesielczyk, Pracka et al, [Changes of sleep quality and mood disorders under the influence of phototherapy in patients with seasonal affective disorders SAD] (Article in Polish), Psychiatr Pol. 2004 Nov-Dec;38(6):1105-14.
(6) Leahy L G, Overcoming Seasonal Affective Disorder, J Psychosoc Nurs Ment Health Serv. 2017 Nov 1;55(11):10-14. doi: 10.3928/02793695-20171016-03
(7) Campbell Institute Symposium Event Summary
(8) Del Valle, Gaby. Do SAD lamps actually work? Vox. 2019, Feb 28.