The Daylight Project, October, 2013
Daylight and its Impact on Fertility
As Infertility Awareness Week begins here in the UK, we catch up with Deborah Burnett – internationally renowned lighting consultant, registered interior designer, and member of the American Academy of Sleep Medicine specialising in light and health.
She is lead author of a new book entitled Evidence Based Lighting Design ( Wiley Publishers Spring 2014 ) which explores how all types of light, including daylight and ordinary light bulbs, iPads and computers, impact our health, well-being and sleep.
Deborah shares her fascinating insights into the connective link between daylight, human health and reproduction.
1. Deborah, it’s fairly well documented that diet, exercise, stress, drinking and smoking can all affect our fertility, but can daylight really affect fertility too?
As humans we are diurnal creatures who are evolutionary aligned to the daily rotation of the Earth as it cycles between the daily, seasonal, and annual patterns of light and dark. In fact we have an innate biological and neurohormonal chemical system linked directly with the 24 hour patterns of light and dark. This is known as the circadian system. The human circadian system is an overarching system regulating important aspects of life such as blood pressure, heart rate, urine output, sleep, wake and reproduction.
A primary component of that system is the circadian rhythm. This is an aligning feature which continually anticipates the environmental conditions of significant importance such as daylight, darkness, and temperature variations throughout a 24 hour period. The two most important signals which align the rhythm to the environment are light and temperature. In addition to naturally occurring daylight and darkness, recent scientific discovery has now demonstrated that electric light and indoor HVAC systems also align the rhythm in the same manner as do daylight and the dark of night.
Since 1978, scientific research has established that human fertility also aligns with the circadian rhythm and natures changing seasonal cycles.1 Examining three key reproductive hormones, Reinberg et.al had demonstrated a 95% confidence rating establishing Autumn as the season of choice for human male fertility and ability of women impregnated during this period to carry full term.
2. When you talk about light playing a role in regulating our body's reproductive system, do you mean natural or artificial light? Does one have more of an impact than the other?
For matters regarding reproductive health, both daylight and electric lighting have the ability to directly influence the human circadian system and align the circadian rhythm. Recently there have been several studies reporting a link between the frequency of spontaneous abortions and light at night when experienced as shiftwork.2
A number of studies have also reported a higher percentage of early foetal loss, preterm births, and lower birth weights for those women who work during the night time hours normally assigned for sleep. It is now believed that the irregular exposure of light and darkness is the primary reason for these conditions as well as an increase in breast and ovarian cancer. In 2007 the World Health Organization ( WHO ) had determined that due to circadian dyschronization of light at night, working the night shift is now classified as causation factor in breast cancer for both men and women.
3. It's pretty easy to fall out of sync with our body's master clock. Many of us work indoors all year, and aren’t exposed to much natural sunlight during the work week. What are the best ways to get round that?
Since the late 1970’s we all have been experiencing a greater dependence on electric lighting for our only source of daytime available light. A dismal condition indeed when you consider that a 2005 Japanese study determined that 60% or greater of all developed countries had populations whose only daily light exposure came from a ceiling fixture. With that in mind, all of us, and not only couples looking to conceive, should adapt their lifestyle to include the following: getting as much exposure to natural daylight as possible, arranging your work place to accommodate your desk or station nearer to windows with direct views to the outside, exercising early in the morning before work without wearing sunglasses, and maintaining a habit of avoiding all unnecessary light exposure at night.
4. So the objective is to understand how our bodies respond to light? Can getting the light our bodies need help our reproductive system function more effectively?
Yes it is extremely important that we all receive adequate direct daylight exposure. The innate ability of our body and brain to receive the necessary protocol of light is much likened to that of a dosing protocol of pharmaceuticals. Depending on age and lifestyle, the timing, duration, exposure, location and spectral distribution of light wavelengths all contribute to account for the optimal amount of light we need each day for reproductive health. And we now know that even our genes are paying attention to the dosing protocol of light and darkness we receive each 24 hour period. With the two primary genes associate with circadian system health, science is painting a clear picture of the importance of maintaining the necessary ‘ingredients’ of quality light found in daylight.
A 2006 study had established what we have long known that the influence of both natural daylight, darkness and exposure to electric light at night (LAN) is a critical element of genetic expression, disease formation, and human well-being. Stating that “emerging evidence demonstrates that the primary clock genes, Clock and Bmal1 (Brain and Muscle ARNT-like protein 1, also known as Mop3), strongly influence reproductive competency.” 3
5. You talk about light affecting female hormones - is light as important for men as it is for women? Are men are particularly influenced by adequate amount of daylight?
Several recent studies have provided evidence that simply getting 20 minutes of daylight exposure each morning can raise testosterone levels as much as 30%. The exposure to natural daylight in the morning also had the added benefit of increasing the quality of sleep on the nights where the men walked in the morning and contributed to the rise in reproductive hormones the following morning.
6. What's your key piece of advice then for a couple having fertility problems? Apart from the obvious!
Unfortunately, the link between environmental light, temperature, and fertility is not clearly understood by the general medical community. The knowledge has been available among scientific researchers linking the circadian cycle of light and dark an it’s impact on fertility and a successful pregnancy attempt but not commonly available even though applying the work to day to day IVF protocols could result in a higher rate of pregnancy by as much as 20%.4
My new book, “Evidence Based Lighting Design: connecting the Dots between scientific discovery, human wellness and Economic ROI” will help to communicate the information for not only the architectural community but also, the clinicians who must embrace the fact that the places where we work, heal, learn, and call home must be considered in the delivery of wellness and reproductive health. Here are a few tips from the book which will offer advice for those seeking to bring the ‘patter of little feet’ into their family:
· Sleep is key: be sure to maintain a regular habit of getting to sleep by 10:00 PM each night and waking the next morning by 6:30
· Avoid light at night: Turn off the ceiling lights 2 hours after sundown each night, install red light bulbs in the hallway for use as night lights, and limit the use of computers and glowing technology making sure to power down at least 3 hours before bedtime each evening.5 By limiting light exposure including computers and television you can allow a darkness derived hormone ( melatonin ) to express on schedule producing the right combination of brain chemicals which provide a quality sleep and ensure a healthy metabolic function; both necessary when trying to conceive.
· Daylight, the drug of choice: Get outside each morning between the hours of 9:30 and 11:30 for at least 20 minutes
· Temperature directives: Take a hot shower each evening at least 20 minutes prior to getting into bed, sleep each night in a cold bedroom between 63 – 68 degrees, allow yourself to get warm or preferably hot during the afternoon hours of noon – 3:00 PM, and limit sweat producing exercise to no later than 4 hours prior to bedtime
7. Just as it’s important in fertility, is receiving adequate amounts of daylight important in pregnancy too?
Emerging light = health research is now paving the way for how to advise pregnant women in getting enough light during critical periods of foetal development. The circadian systems of both mother and foetus are both linked to the cycles of light and dark 6 and when this is disrupted miscarriage can occur. During a robust study using a mouse model simply allowing pregnant females to experience simulated jet lag, the same as flying between Chicago and London resulted in a 78% spontaneous abortion rate.7
Another new study demonstrated the importance of moms getting the correct dose of light exposure during the critical first trimester. Again using a mouse model, these researchers discovered that essential components of vision developed only when pregnant females received light level exposure to what would translate to the 10th week gestation in human terms.8 In fact, the lead research scientist has been quoted as saying that in the future a “light prescription” will be ordered for pregnant women ensuring that the developing fetus receive the necessary component of light and darkness to regulate retina development and vascularity.
8. Is there any research addressing the topic of daylight for healthy newborns?
Since all humans require a healthy balance of bright light during the daylight hours and complete darkness during the evening hours, it is no wonder that the results of several studies should come as no surprise. An interesting investigation into the light reactive neurotransmitter serotonin examines the circadian influences of temperature and light on the prevention of SIDS ( sudden infant death ).9 Discovering that this non pharmacological intervention can be instrumental in prevention of this tragedy is an important discovery: unfortunately, this critical lifesaving information is not getting out to parents of newborns.
With that, I challenge all readers of this article to pass along the following tips to all pregnant family members, new moms, and practicing obstetricians: In addition to placing a new born thru 6 months of age on his back to sleep, to further reduce the opportunity of SIDS by a whopping 94%, all parents should be sure that bright daylight is flooding the room where the child is napping, the room temperature is no higher than 72 degrees, and that either a ceiling or table fan are oscillating at high speed in the room where the newborn is napping. At night, do the same thing except making sure that the room is perfectly dark, and, if you have to use a nightlight, make sure the bulb is red; not amber or soft white, but an actual red color similar to that of an ordinary red Christmas light bulb.
Deborah Burnett, ASID, CMG, LGC, AASM
Deborah is an award winning internationally recognised registered interior designer, keynote presenter and member of the American Academy of Sleep Medicine. Over a successful 30 year professional career, her practice has emerged as a leader in the embodiment of intent-driven, evidence-based architectural and interior design devoted to a working knowledge of how the body and brain are directly affected by the built environment.
An early pioneer in the emerging practice of EPIGENETIC DESIGN, she has been instrumental in disseminating important scientific and medical research examining the impact of built environmental ambient lighting on the process of sleep, cognition and obesity. In addition to consulting on projects throughout the world, Deborah’s work includes clinical and academic research, public education and outreach, academic lectures, and presentations in the popular media.
- Reinberg A, et.al.( 1978) Circadian And Circannual Rhythms In Sexual Activity And Plasma HormonesArchives of Sexual Behavior Volume 7, Issue 1, pp 13-30
- Nurminen T. ( 1998 ) New challenges for the organization of night and shift work: Proceedings of the XIII International Symposium on Night and Shift Work, 23—27 June 1997. Scandinavian Journal of Work, Environment & Health Vol. 24, Supplement 3., Finland (1998), pp. 28-34
- Boden, M et.al ( 2006) Circadian Rhythms And Clock Genes Appear To Be Involved In Optimal Reproductive Performance, Reproduction Journal Vol (132) PP: 379-392
- Wood S., et al ( 2006) Seasonal variation in assisted conception cycles and the influence of photoperiodism on outcome in in vitro fertilization cycles. Human Fertility 2006, Vol. 9, No. 4 , Pages 223-229 (doi:10.1080/14647270600806557)
- Wood B, Figueiro G, et.al ( 2012 )Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression. Applied Ergonomics, 2012; DOI:10.1016/j.apergo.2012.07.008
- Mirmiran, M., Ariagno, R.L. et.al ( 2003 ) Development Of Fetal And Neonatal Sleep And Circadian Rhythms Sleep Medicine Reviews, Vol. 7, No. 4, p. 321±334, doi:10.1053/smrv.2002.0243
- Summa KC, Vitaterna MH, Turek FW (2012) Environmental Perturbation of the Circadian Clock Disrupts Pregnancy in the Mouse. PLoS ONE 7(5): e37668. doi:10.1371/journal.pone.003766A
- Rao, S., Lang, R. et al. ( 2013 ) A Direct And Melanopsin-Dependent Fetal Light Response Regulates Mouse Eye Development. Nature, 2013; DOI:10.1038/nature11823
- Coleman-Phox, K. et.al ( 2008 ) Use of Fan during Sleep and the Risk of Sudden Infant Death Syndrome. Arch Pediatr Adolesc Med. 162 ( 10) Pp: 963-968