Light, Circadian Rhythm, Melatonin, Eyes, Blue Light. What does all this mean for our health?
Our bodies are inescapably intertwined with nature’s cycles – the seasons, the months, the moon, and the 24 hour cycle of day and night. Light – specifically, the light from the sun is incredibly important in the biological processes which take place in our body. As Globe at Night says:
“In disrupting ecosystems, light pollution poses a serious threat in particular to nocturnal wildlife, having negative impacts on plant and animal physiology. It can confuse the migratory patterns of animals, alter competitive interactions of animals, change predator-prey relations, and cause physiological harm. The rhythm of life is orchestrated by the natural diurnal patterns of light and dark; so disruption to these patterns impacts the ecological dynamics.
With respect to adverse health effects, many species, especially humans, are dependent on natural body cycles called circadian rhythms and the production of melatonin, which are regulated by light and dark (e.g., day and night). If humans are exposed to light while sleeping, melatonin production can be suppressed. This can lead to sleep disorders and other health problems such as increased headaches, worker fatigue, medically defined stress, some forms of obesity due to lack of sleep and increased anxiety. And ties are being found to a couple of types of cancer. There are also effects of glare on aging eyes. (See text below.) Health effects are not only due to over-illumination or excessive exposure of light over time, but also improper spectral composition of light (e.g., certain colors of light).”
Don’t get me wrong…we need light — we need sunlight! I don’t buy the skin cancer hype one bit — when spring hits, I start building my sun tolerance, starting with 10-15 minutes at a time, making sure my arms and hands are exposed. As long as I’m not spending every hour of the day in the sun at the equator of the Earth, and I’m not forming sun burn, and I’m eating antioxidant-richfoods, I’ll be fine – in fact, I’ll be more than fine! All the amazing cells in my skin will be producing sulfate. Sulfate is an incredible thing MIT researcher Stephanie Seneff has been studying for many years. Her studies show a fascinating circular link between sunlight exposure (sulfate production) and melatonin production (facilitating effective sleep, and so many other things).
“There are many biologically active molecules that are sulfated for transport in the blood. Some of these are cholesterol, vitamin D, serotonin, and melatonin. Melatonin delivers lots of sulfate to the cerebral spinal fluid. Melatonin is derived from serotonin and serotonin is derived from tryptophan, which is a product of the shikimate pathway. This takes us right back to glyphosate, because it interferes with all of this.” – Stephanie Sennef interview posted on Vaccine Impact
What does this mean exactly? It means that having enough sulfate in the body allows the melatonin (your body produces) to get where it needs to go and do its work. We make sulfate during the day when exposed to light, and we use that sulfate to transport melatonin, which we can only really produce when there is absence of light. This is just one example of how embracing the light and the darkness can optimize health!
There are many other examples showing how our bodies use sunlight…
“mammalian cells are capable of extracting energy directly from the sun through the help of plants in the diet” – GreenMed Info
And if we disregard nature’s cycle of light and dark?
“researchers put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.
Even dim light can interfere with a person’s circadian rhythm and melatonin secretion. A mere eight lux—a level of brightness exceeded by most table lamps and about twice that of a night light—has an effect, notes Stephen Lockley, a Harvard sleep researcher.” – Harvard health letter
“Animal studies have reported that exposure to very low levels of light at night (5 lux—about the amount of light from a child’s night light 2 meters from your face), causes a host of problems for rodents including increased risk of some types of cancer, impaired immune function, deranged metabolism, and alterations in cognition and mood.” – Randy Nelson, Huffington Post
“Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).
In another study of blue light, researchers at the University of Toronto compared the melatonin levels of people exposed to bright indoor light who were wearing blue-light–blocking goggles to people exposed to regular dim light without wearing goggles. The fact that the levels of the hormone were about the same in the two groups strengthens the hypothesis that blue light is a potent suppressor of melatonin. – Harvard health letter
Getting out in the sun every day can be a super challenge, especially for those who work indoors. And since we learned to harness electrical energy to light up the night, we have changed our lifestyle habits to the point where it is impossible to avoid artificial lighting at night! These changes in lifestyle habits do actually affect our health (our melatonin production, and the cascading biological processes). Further, the blue light emitted from LEDs and other light bulbs, and from our electronic devices, is particularly disruptive, because the amount of blue light emitted from LEDs is much higher than the other types of light they emit — the ratio is severely imbalanced, as you can see in the picture below.
“Prior to light bulbs, people slept an average of 10 hours a night. Nowadays, the average American gets less than seven hours of shut-eye. Why is that? As noted by Authority Nutrition:1
It turns out that perhaps the single biggest contributor to our collective sleep problems is the use of artificial lighting and electronics at night. These devices emit light of a blue wavelength, which tricks our brains into thinking that it is daytime.”
A related part of this problem is the fact that most people work indoors and fail to get sufficient exposure to full, bright, and natural sunlight during the day. This disconnect from the natural cycles of day and night can turn into a chronic problem where you’re constantly struggling to fall asleep and stay asleep.
Fortunately the remedy is both simple and inexpensive, as all you have to do is modify your light environment to resynchronize your body to the natural cycles of light and dark.
The story of light and our health is not just about lumens (amount of light emitted)…
it’s also about lux (intensity of the light on a surface or in an area. We see light focused on a small area as very bright, whereas we see light spread in a wide beam over a bigger area as a weaker light. Sunny days might have 150,000 lux, whereas an overcast day might be 1,oo0 lux. The lamp, overhead light, and lamposts might generate 50-500 lux, but to adequately prepare your body for sleep, you should have less than 180 lux). If you’re thinking “but the moon emits light! Are you going to tell me the moon is bad for me too?” – know that the moon generates light less than one lux, and less than 1 lumen! To me, this means that the light in a bedroom should not exceed 1 lux.
To understand more about this in terms of various light sources (sun vs. bulb, and which type of bulb), and what causes macular degeneration, read the following excerpts from Dr. Mercola’s book “Fat for Fuel.”
“As you can see in the picture below, sunlight is perfectly balanced. It contains amounts of red and blue light and is also balanced with infrared, near-infrared, and ultraviolet light further complementing its health benefits. As you can see from this, we are designed to have blue light exposure in the early-morning hours but not in the evening and nighttime hours.
[As is the case with whole food]…we benefit from the various types of light when we are exposed to it in its whole form, and in the right context (the sun). So while blue light is not inherently dangerous, it is when taken out of its proper biological context that is causes harm.
We have established that our melatonin is severely suppressed when we are exposed to light after sunset, and especially when we are exposed to blue light after sunset, but not many understand that this non-sunlight blue light exposure is also problematic during the day. Studies clearly show that blue exposure from LED or fluorescents increases ROS (reactive oxygen species*) in the retina, but this is only problematic when the blue light comes from an artificial source. This is especially true when you are indoors and have no access to natural light from a window. Blue light from sunlight is balanced by the red and infrared frequencies that are also present in sunlight, and these stimulate the repair and recovery pathways that help the retina and your body recover from blue light exposure. Many studies show that exposure to blue light from LED lights contributes to macular degernation, as blue light penetrates more deeply into the eye than UV light and can reach the retina, where the oval-shaped macula is located.
Although if macular degeneration is caught early, its progress can be slowed, the vision loss it causes is typically irreversible and if left unchecked will become severe. While no one can dispute the energy savings gained from digital lighting, virtually no one is exploring the biological consequences of this shift. …we may be dealing with a massive dose of unintended consequences, substituting energy savings for vision loss.
To more clearly understad the danger blue light poses to your eyes, it’s helpful to look to the color-rendering index (CRI). The CRI describes how a light source makes the color of an object appear to human eyes and how well subtle variations in color shades are revealed. Using a scale from 0 to 100, it indicates how accurate a “given” light source is at rendering color when compared to a “reference” light source.
The higher the CRI, the better the color rendering ability. Light sources with a CRI of 85 to 90 are considered good at color rendering. Light sources with a CRI of 90 or higher are excellent. Full sunlight has a CRI of 100.
Most incandescents have a CRI of 99, while most LED bulbs have a CRI in the low 70s. While incandescent bulbs are “inefficient” because less than 5 percent of the energy they consume is used to produce visible light, the rest of the energy is converted to heat, another term for infrared light.
While we certainly can’t use that “wasted” energy from the incandescent bubs to see, it is a thermal source of lighting and produces a very similar wavelength distribution as sunlight. The “wasted” nonvisble wavelengths appear to have great biological value.
Many human studies need to be done to confirm the biological effects of LED light exposure, but that does not mean you need to wait decades for the resut and suffer from this exposure until everyone agrees we need more balanced sources of light.
Additionally, LED lights are digital and such flicker, or go no and off, at a very high frequency that may have some negative biological consequences.
“Although any kind of light suppresses melatonin, research shows the worst offender is light with blue wavelengths. LED bulbs, though hailed for their energy efficiency, are dominant in blue light and suppress melatonin five times more than orange-yellow light bulbs. One study showed that exposure to room light (compared to dim light) before bedtime shortened melatonin duration by about 90 minutes, and that exposure to light during usual sleep hours suppressed melatonin by greater than 50 percent.” – www.functionalhealthminute.com.”
We’ll see how Dr. Mercola’s prediction about macular degeration plays out as the generations of LED smart phone and laptop users age!
Light is so delightful, but we can abuse it. Three Main Types of Light Pollution (in addition to over-illumination and clutter), borrowed from “Globe at Night“:
- Glare – from unshielded lighting is a public-health hazard—especially the older you become. Glare light scattering in the eye causes loss of contrast, sometimes blinds you temporarily and leads to unsafe driving conditions, for instance.
- Light trespass – occurs when unwanted light enters one’s property, for example, by shining unwanted light into a bedroom window of a person trying to sleep
- Skyglow – refers to the glow effect that can be seen over populated areas. Skyglow is the combination of all the reflected light and upward-directed (unshielded) light escaping up into the sky (and for the most part, unused)
Shielding lights significantly reduces all three of these types of light pollution. Find more info at the Globe at Night website.
Want to visit a place where you can see the stars in all their glory? Visit the International Dark Sky website to find the darkest international dark sky reserves, and take a vacation! http://www.darksky.org/idsp/
Enjoy this list of ways to optimize your health, and get back to nature (a little bit)!!!! 🙂
- Adjust your schedule so that you wake with the sun and sleep with the sunset! This can be hard, becuase so many people like to party at night, but think of it as a romantic challenge to connect with a part of ourselves we may have forgotten, and see what happens!
“Get outside first thing in the morning, and look right underneath the sun — no glasses, contacts or sunglasses. This will normalize your hormones and sleep patterns like nothing else.” – Nick Pineault
- “Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.” –Harvard article. “When you spend all or a majority of your day indoors, you essentially enter a state of “light deficiency.” The reason why light intensity is important is because it serves as the major synchronizer of your master body clock, which is composed of a group of cells in your brain called the suprachiasmatic nuclei (SCN). These nuclei synchronize to the light-dark cycle of your environment when certain wavelengths of light enter your eyes. You also have other biological clocks throughout your body, and those clocks in turn synchronize to your master clock…. Your pineal gland produces melatonin roughly in approximation to the contrast of bright sun exposure in the day and complete darkness at night. If you’re in darkness all day long, your body can’t appreciate the difference and will not optimize melatonin production.” – Dr. Mercola
- “If you wake up before sunrise, use blue-light blocking glasses until the sun rises.
- get at least 10 to 15 minutes of light first thing in the morning. This will send a strong message to your internal clock that day has arrived, making it less likely to be confused by weaker light signals later on. This will help your circadian system reset itself.around solar noon, get another “dose” of at least 30 minutes’ worth of sunlight. A full hour or more would be even better. If your schedule is such that you have to get up and arrive at work before sunrise, aim to get at least that half hour of bright light sometime during the day.” – Dr. Mercola
- Make your home lighting melatonin-friendly.
- use as few lights as possible at night in your home.
- choose only incandescent bulbs – no LEDs, no CFLs.
- We saw in the Harvard studies that light as low as 5 lux is the activation range within which light will begin to suppress melatonin production. However, wavelength is also important. Make sure they are low wattage, and
- for the bedroom, you might even consider a candle with an old-fashioned wax plate, especially if you need light in the middle of the night, but try to avoid light in the middle of the night.
- If you have to stay up past sundown, wear blue-light blocking glasses ($69) or cheaper ones here ($59) and ($27), to remove the most disruptive parts of the bright lights. These $8 glasses are often recommended, but they are so big that they fall off my face, so I didn’t keep them. I’ve tried wearing the blue light blocking glasses a few times while driving at night as well, because more and more cars now have LED headlights – these super bright headlights feel so harsh and my eyes start hurting and I get headaches! I don’t know if wearing these blue light blocking glasses while driving at night is truly safe though….does it make it harder to see some things? I have worn them in public, and would like to try doing this more. I’ve had to field a few questions about them, so be prepared for a few if you try it.
- Turn off your outside lights. Outside light pollution negatively decreases health of nocturnal animals (just like us! night shift workers have an increased cancer risk), and decreases their reproduction, confuses migratory birds who fly at night — even frogs refrain from singing their mating choruses in artifical light.
- Make sure your bedroom is DARK , and not lit by outside lights, other than the stars and the moon. If your neighbors have outside lights, or you live near a lamp post, buy black-out curtains. You should not be able to see your hand in front of your face – your room should be dark!
- Lighting is the primary source of LED exposure, computers, phones, TVs, etc, are emitting blue light as well. Install solutions to block the blue light emitting from these electrical devices
- iPhones: activate the Night Shift in settings
- Android phones: activate the blue light filter settings, or download an app like “Twilight”
- computers: download Iris, which is far easier to use and provides better blue light filtering than compared with the f.lux program. You can find information about why I like the app in the post titled: “Eyes Tired? Eye degeneration? You need to know about Iris!“
- Do not use these LED devices at least one hour before bedtime.
- Use an alarm clock that has an option to turn off the lit display, or cover it with a hand towel at night
If one is still having trouble with melatonin, perhaps the diet should be examined. Glyphosate, the active ingredient in RoundUp weedkiller, and the active ingredient in all herbcides applied by lawn care companies and applied by farmers, blocks the shikimate pathway in the plants grown in the soi sprayed soil. If the shikimate pathway is blocked, the plants cannot produce three of the essential amino acids they normally make, and which we as humans need to obtain from plants in our diet. One of these three essential amino acids is tryptophan. Melatonin is derived from seratonin, and seratonin is derived from typtophan. Makes you think twice about that slice of what bread! (Wheat is heavily sprayed with glyphosate just before harvest to dramatically speed up the drying time (grain crops like wheat need to be dry before they can be harvested; however, glyphosate is sprayed on a variety of vegetables as well, and of course, the genetically modified (GMO) crops designed to survive heavy sprayings of glyphosate (soy, corn, sugar beets, etc).
*ROS (Reactive oxygen species) – ROS are molecules that contain oxygen atoms that have gained one or more unpaired electrons, making them very unstable. These highly reactive atoms form potentially destructive free radicals. …They create a snowball effect – as molecules steal electrons from one another, each one becomes a new free radical, leaving behind a trail of biological carnage. These collect within the cell and disintegrate cell and mitochondrial membranes (lipid peroxidation), damage DNA by disrupting replication and maintenance, but under normal physiological conditions they regulate crucial cellular functions, such as creation of melatonin and nitric oxide, optimize metabolic signal pathways, biological signals that respond to environmental stressors, and play positive roles in benefits during exercise. ROS in excess are damaging. You can reduce the ROS your body produces with an eating program like Dr. Mercola’s Mitochondrial Metabolic Therapy (MMT), which emphasizes healthy fats (animal fat, coconut oil, olive oil, but moderate amounts of dairy fat, as these still contain some protein), reasonable animal protein intake, vegetables, and low net carbs (not many starches like sweet potatoes or sugars like fruits and even dates, some berries and grapefruit are ok), and keeping nonfiber carbs to 50g per day or less. – “Fat for Fuel by Dr. Mercola