In the last post, I talked about how good sleep is one of the most important foundations of mental health. When we sleep well, we feel better, physically and mentally, and good sleep is a key factor in preventing depression and anxiety. In this post, I will explain ways in which healthy sleep is closely linked to our “light diet” (the type and and amount of light you receive each day).
How Does Light Impact Our Health?
Every living thing on Earth has been shaped by our nearby star – the Sun. Until very recently, pretty much ALL the light humans (and everything else on Earth) were exposed to came from the Sun. Our bodies are built to rely on and react to sunlight in crucial ways that affect our physical and mental health. Think of sunlight as a collection of essential nutrients, and the type and amount of light you receive as your “light diet.” According to Dr. John Ott, “… when trace amounts of certain wavelengths of light are missing from your ‘light diet,’ this can have a staggering effect on your health.” I would add that TOO MUCH of certain wavelengths can also have a staggering influence, as shown below.
Sunlight contains all the wavelengths/colors of the visible light spectrum. Human bodies are adapted to use all these wavelengths for important biological processes. Various wavelengths impact our bodies by doing things like powering up cells, regulating hormones and neurotransmitters, and balancing our moods. In addition, thousands of studies have shown how certain light wavelengths also enhance physical performance, speed recovery from stress, increase alertness, and positively affect the expression of our genes. One very well studied aspect of our light diet is the impact of certain types of light on sleep—which is most affected by blue light.
Healthy “Light Diet” = Better Sleep = Improved Mental Health.
The pattern of waking during the day when it is light and sleeping at night when it is dark is a natural part of human life, and that pattern is regulated by the light from the sun into our brains. Certain wavelengths/light colors regulate melatonin, the hormone produced in the pineal gland that is responsible for regulating sleep. The main light color related to the melatonin cycle is the blue part of the spectrum. In the natural cycle, when our eyes stop receiving blue light from the sun, the body begins production of melatonin and prepares to sleep. Unfortunately for our sleep cycles, blue light is now everywhere, all the time. As a result, this constant exposure to blue light at night disrupts the melatonin cycle, which can severely disrupt sleep.
Our Blue Light Exposure Is Out Of Control
Blue light is absolutely necessary for our health, provided we are exposed to it in the right amounts as part of the complete visible spectrum, and at the appropriate time. However, that exposure has become difficult to control. First, we live our lives mostly indoors and many people do not get much exposure to the full spectrum sunlight. In addition to natural sunlight, there are many man-made, indoor sources of blue light which include fluorescent and energy efficient LED lighting. Most notably, LED light bulbs, computer display screens, electronic notebooks, and smart phones emit significantamounts of high-energy visible (HEV) blue light.
This has contributed to the rise in sleep problems suffered by many modern people. High energy visible (HEV) blue light, especially from electronic devices and LED lights, has been all over the news lately, primarily warning about sleep interference. There are thousands of studies that show the negative impact and outright harm to sleep (and other elements of health) caused by excessive blue light exposure. The mechanism for sleep interference I talked about above is well documented. But it is still hard to control exposure to blue light from all sources.
How To Take Control Of Your Blue Light Exposure And Promote Healthy Sleep
First, don’t fight biology. We are all biologically adapted to the sun, and excessive blue light exposure does disrupt the melatonin/sleep process. The biology is not going to change, so we will have to focus on things we can control — like the devices that emit blue light, and how much of it reaches our eyes.
We must control blue light exposure, especially after sundown. Most people are not going to eliminate all the sources of nighttime blue light (or excessive unbalanced day time blue light), even if it were possible. I am not asking you to get rid of all LED screens and devices like computer monitors, TVs, smartphones and tablets, let alone energy efficient LED and CFL lights. Here are some things that anyone can do to limit junk light and promote good sleep.
- Filter it. In the past few years, manufacturers and programmers have come up with blue light filter applications like f.lux, or NightShift, as well as settings such as Night Mode on iOS. It is important to use those tools wherever you can.
- Block it. If we can’t eliminate junk light, we can at least block it from reaching our eyes. The easiest, most effective way to block blue light is by using glasses designed to filter junk light and prevent overexposure to blue light. You can buy blue-light blocking glasses in many places, including Amazon – just search for “blue light blocking glasses.” By putting on the glasses in the evening, you can still watch TV, work on a computer, or use your phone, while supporting the natural processes that promote good healthy sleep. In the picture below, I am wearing glasses made by TrueDark. (I don’t have any affiliation with the company and am not receiving any compensation for mentioning them. I am simply a satisfied user of their high-quality glasses.)
- Get some morning sunlight on your eyes every day. Sunlight contains blue light, along with all the other wavelengths of the visible spectrum, in a balanced Light Diet. Getting all of that light on your receptors at the right time of day (morning) is important to getting your sleep cycle functioning at its best.
Try controlling your blue light exposure at night for better sleep. The next post will talk about other elements of light and mental health.