ASID: The Case for Darkness
I’m finally beginning to feel like my old self! It’s been rough since the Spring Equinox and the roll back to daylight savings time, but my biological clock is finally entraining to longer days and shorter nights. And I’m not alone.
Recent studies have also shown an increase in cardiac admissions and a rise in traffic accidents to occur during the two week period following the transition to daylight savings time (Kantermann, T. et al 2007). Sure, blame it on the loss of an hour’s sleep, but my spin is that we humans are also keying in on the unusual equality between light and dark during the celestial Spring Equinox, thus bringing about the fractured sleep, daytime fatigue, and an unsettling feeling of unease so many experience. So when a few hours of unusual light cues and an hour of sleep loss, what happens when we continually push with ever-increasing 24/7 artificial light at night? Could it be a disruption so great to the human system to bring about a rise in the occurrences of cancer, obesity, metabolic syndrome, ADHD, and many other modern day afflictions?
This is not a new question. In 1963, Wurtman and colleagues first reported that nighttime melatonin synthesis in the pineal gland was under the inhibitory control of light. Since then, we’ve known that the delicate balance of environmental light and dark played a major role in our overall health, yet we continue with wholesale indiscriminate use of bright nighttime artificial light. And this is especially concerning when you consider that less than 10-foot candles of room light during a period naturally intended for darkness is enough to suppress a major hormone; it is a tribute to our body’s designer that we are functioning as well as we have under the glare of artificial, 24/7 light (Zeitzer J. et al 2000).
So what role does the designer of the built environment play in all of this? First of all, I’m not suggesting that we take the blame or forgo the use of artificial light after dark, but rather that we, the entire A&D community, dig deeper into the evidence-based data on how light and darkness affect the human body and brain, and then apply that research to not only patient rooms, but every space we design: from public gathering areas and workplace environments, to residential homes and bedrooms. Every building we construct, every room we design must be crafted with a skill set including knowledge of how we are dependent on light zeitgerbers such as daytime blue wavelength light, a midperiod of white to red shifted evening light, and sustained low-light darkness at night in order to correctly signal bodily and neurological functions necessary for our healthy survival. And once we collectively decide to support the body and brain with our creative efforts, we will be designing with darkness in mind.
Duffy, J.F. et al (2005) Entrainment of the human circadian System by light BIOLOGICAL RHYTHMS 2005 Aug; 20(4): 326-38
Kantermann, T. et al (2007) The human Circadian clock’s seasonal adjustment is disrupted by daylight savings time. CURRENT BIOLOGY 2007 Nov 20;17 (22);1996-2000.Epup 2007 Oct 25.
Wurtman, R.J. et al (1963) Melatonin synthesis in the Pineal gland: control by light. SCIENCE 1963 Nov 22; 142:1071-3
Zeitzer et al (2000) Sensitivity of the Human Circadian Pacemaker to nocturnal light: melatonin phase resetting and suppression. JOURNAL of PHYSIOLOGY 526.3, 695-702