DAYLIGHT AND ITS IMPACT ON FERTILITY
From The Daylight Project
The amount of light we are exposed to plays a crucial but little-known role in human reproduction, from improving fertility in both women and men to helping foetal development.
We caught up with internationally renowned lighting consultant Deborah Burnett - author of Evidence Based Lighting Design – to get her insights into the relationship between daylight, human health and reproduction and to get her advice on ways to increase the amount of daylight we get each day.
It’s fairly well documented that diet, exercise, stress, drinking and smoking can all affect our fertility, but can daylight really affect fertility too?
Essentially, we humans are diurnal creatures and we’re all aligned to the daily rotation of the Earth. Our body clocks are intrinsically linked to daylight. To understand how that body clock works, is to really understand fertility and hormonal balance.
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, and it regulates important aspects of our lives such as blood pressure, heart rate, urine output, sleep, wake and even reproduction.
A key part of the circadian system is what is known as the circadian rhythm. It aligns our bodies to, and continually anticipates the environmental conditions that are important to our health and wellbeing - like daylight, darkness, and temperature variations - throughout a 24-hour period. The two most important signals the circadian rhythm uses to do this are light and temperature.
Scientific research has established that human fertility also aligns with the circadian rhythm and nature’s changing seasonal cycles. For instance a study in 1999 established Autumn as the season in which women are most able to get pregnant and carry to full term.
Do you mean natural or artificial light? Does one have more of an impact than the other?
When it comes to reproductive health, both daylight and electric lighting can directly influence the human circadian system. Several studies have illustrated the benefits of getting the right kind of light at the right time. In fact, it’s now believed that irregular exposure to light is the primary reason for a number of complications in conceiving and carrying to full term.
Indeed it is believed that following natural patterns of light during the day and dark at night, can help to minimise risks of complications in pregnancy. Several studies have reported a higher risk of complications in pregnancy for those women who work during hours we’d naturally be sleeping. Regular sleep patterns and exposure to light and dark at the right times are therefore factors to consider in enhancing chances of conceiving and carrying to full term.
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 have all been experiencing a greater dependence on electric lighting – often it can be our only source of light during the daytime. A Japanese study in 2005 determined that 60% or more of all developed countries had populations whose only daily light exposure came from a ceiling fixture.
It’s not only couples trying to conceive that this applies to; all of us can improve our wellbeing by:
• 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 world
• Exercising early in the morning before work (without wearing sunglasses)
• Getting into the habit of avoiding all unnecessary artificial light exposure at night
You talk about light affecting female hormones - is light as important for men as it is for women?
Several recent studies have shown evidence that simply getting 20 minutes of daylight exposure each morning can raise testosterone levels as much as 30%.
Exposure to natural daylight in the morning also has the added benefit of increasing the quality of sleep that night and also contributed to the rise in reproductive hormones the following morning.
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 linking the circadian cycle and its impact on fertility and a successful pregnancy attempt is not commonly available, even though a 2006 study showed that applying the work to day-to-day IVF protocols could result in a higher rate of pregnancy by as much as 20%.
My new book will help to communicate the information, not only for 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 of my tips from the book which will offer advice for those seeking to bring the ‘patter of little feet’ into their family:
Is receiving adequate amounts of daylight important in pregnancy too?
Health research is now paving the way in offering advice for pregnant women to get 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 and when this is disrupted, the risk of miscarriage can occur.
A recent study demonstrates the importance of mothers getting the correct dose of light exposure during the first trimester. Using mice, 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.
In fact, the lead research scientist predicted that in the future a “light prescription” will be ordered for pregnant women to help ensure that the developing foetus receives the necessary component of light and darkness, to regulate retina development and vascularity.
Is there any research addressing the topic of daylight for healthy new-borns?
Since all humans require a healthy balance of bright light during the daylight hours and complete darkness during the evening hours, 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). Discovering that this non-pharmacological intervention can be instrumental in prevention of this tragedy is an important discovery.
There is a lot of advice that can be hugely beneficial for parents of new-borns and the positive impact that daylight can have at all stages is an important factor to consider.
With that I would encourage all readers of this article to pass along the following tips to all pregnant family members, new mothers, and practicing obstetricians:
In addition to placing all babies from birth to 6 months of age on their back whenever they close their eyes to sleep, it is possible to further reduce the risk of SIDS by a whopping 94% by ensuring a few simple changes are made to the room where the child is sleeping or napping. These include