In a recent article where we discussed circadian lighting, we touched upon how sensitive the circadian clock is to disruptions in natural lighting. We also noted the effects of what can happen when that circadian cycle is disrupted. Mess with the clock, and one can have all sorts of negative consequences stem from it, from unchecked weight fluctuations to depression.

While that article exclusively focused on how circadian systems can be used to correct circadian disruptions, one circadian rhythm expert has a decidedly different opinion. Instead of getting artificial lighting to look more like natural light, Till Roenneberg, a professor emirate of Chronobiology at Ludwig-Maximillian University in Munich Germany, says that more innovation needs to be going into getting that natural light deeper into buildings.

Long a proponent of more architectural solutions, Roenneberg’s emphasis on natural lighting in buildings comes from his focus on the circadian rhythm. It has also led him to be a vocal critic of daylight savings time (DST), while also proposing a theory known as ‘social jetlag,’ wherein differences between human social clocks and circadian clocks can lead to disruptions throughout each week. To Roenneberg there is, quite literally, no substitute for natural light in our eyes.

“Architects have to invent ways to mirror the light from the roofs of our buildings into the ceilings of our offices,” said Roenneberg. “[Lighting scientists and professionals] know that, but I don’t see anybody doing it or developing better technologies to do it. We have to harvest the natural daylight that is on the roof of every building, without diminishing it, and get it into the ceilings of our offices.”

Of course, what Roenneberg is claiming is not an all or nothing scenario. Across lighting experts, the general consensus still holds that artificial lighting systems can still be useful in entrainment when used to support natural lighting. Ideally, buildings should include both natural and electric light sources, though Roenneberg is clear in criticizing the currently ‘limited’ scope of getting light into buildings and noting opportunities for improvement or development of newer, more advanced solutions.

“Electric light can also adjust body clocks to match 24-h days, but natural daylight is usually 100 to 1000 times brighter than indoor light (Wright et al., 2013) and therefore more effective,” Roenneberg wrote in a 2019 paper in the Journal of Biological Rhythms. “We must recognize the important role of light in shaping our daily behavior and the important role of our body clock in maintaining our health and well-being.”