LED lighting systems are always praised for their durability and low cost, but from another perspective, their most important quality is their flexibility in terms of controlling light intensity, spectrum, and duration. These control options are poised to be very important in the coming days, as we continue developing knowledge on the effects of lighting on our health and productivity. 

Indeed, there is a growing body of evidence to the effect that lighting can affect melatonin production and secretion, and consequently affect sleeping patterns. However, there’s not much in the way of actual research findings, seeing as most studies have been done in tightly moderated laboratory conditions. 

To address the need for large-scale, real-world studies on the subject, the U.S. Department of Energy (DOE) has hosted several roundtable forums with lighting and physiology experts and LED manufacturers with a view of drafting a workable R&D program. This move is quite commendable as it’s not often you see experts from completely different, unrelated fields come together to exchange notes and solve social problems. 

The most recent roundtable meeting was held in Washington D.C., and one of the notable contributions was made by Steven Lockley, from the Harvard Medical School. He pointed out that the effects of light on our alertness, heart rate, body temperature, and melatonin production is pretty much open knowledge. His colleague, Shadab Rahman seconded him, adding that removing, or considerably reducing the “blue” factor in light can reverse the effects of exposure to light right before bed. 

Other scholars in attendance, such as Gena Glickman from the University of California and San Diego (UCSD) noted that duration and intensity of the light and the type of exposure (intermittent or continuous) can also affect human physiology to the same level as spectral content. Industry expert Wouter Soer, of Lumileds, also stressed the importance of finding a healthy balance between the positive impacts of lighting (illumination) and its negative effects.

Real-World Studies

As previously mentioned, most of what we know about the non-visual physiological effects of light is abstract and mostly theoretical. Moving forward, we need to do more real-world tests and studies to determine the nature and extent of physiological responses triggered by light stimuli. 

To this effect, the DOE has sponsored multiple research programs, one of which was carried out by Glickman and fellow UCSD researchers. The study’s main objective is to find ways to improve the alertness and circadian health of night workers after exposure to lighting systems for hours on end. In particular, the study seeks to address the aspects of circadian phase resetting, and acute alertness, which is geared to improving people’s concentration levels when working.

The DOE is also working with the Virginia Tech Transportation Institute to study how different types of roadway lighting affect melatonin levels in road users (drivers, pedestrians, and people living near roads). The study focuses on five of the most common light sources used in highways and is expected to provide more realistic insights on the effects of nighttime light exposure to different groups of people. This particular study was considered so important, that the DOE’s SSL board classified it as a priority and awarded it a sizable budget to boot. 

The DOE is also implementing the SSL Gateway Program – a collection of studies designed to test the full spectrum of human physiological responses to various forms of lighting. A number of the studies in the program involve using dynamic LED lighting systems in sensitive environments like classrooms, senior care homes, and medical institutions to not only determine their non-visual effects and the resulting responses among participants, but also measure the potential energy savings. If you wish to track all the Gateway studies and their results, head on over to www.energy.gov/eere/ssl/gateway-tunable-lighting-projects.

It is evident that lighting systems can affect our health, mostly in negative ways. To better protect ourselves, while still reaping the benefits of lighting, we need to find ways to counter these effects. And that can only happen when we have enough fact-based data, which is why studies by agencies like DOE are of great importance. 


Reference: LD+A Magazine – December 2018