Taking a look at the dark side of light
Most readers are familiar with the main pillars of ancestral health including diet, movement, and exercise. The role of sleep and stress management in overall health has gained a lot of attention lately, both in the media and here on our blog. But what about light? Could something so simple and ubiquitous as light really affect our health? The answer may surprise you.
The modern world has reshaped our health in many ways–from industrialized food and sedentary lifestyles, to the pervasive stress and anxiety induced by social media and frenetic work schedules. But perhaps no feature of modernity has influenced our health as much as light. Just think about it for a moment. Electric light didn’t even exist 200 years ago and hasn’t been widely used for more than 100 years, but its all around us all the time. Through most of human history we operated more or less during daylight hours. We woke with the sun, worked and lived in the sunlight, and gathered around community fires in the evening. There’s no telling how late we stayed up, but our ancestors certainly didn’t work night shifts under fluorescent lights or stare at a backlit LED screen for hours each night.
As the importance of circadian rhythm and its connection to optimal human health comes to the fore even in the mainstream medical communities, we have become increasingly aware of the impact that light exposure has on our overall health. This is because light itself is the chief input to setting the circadian rhythm–the regular alteration of light and dark cycles.
But not all light is created equal. Light from the sun consists of a full spectrum of color, from the warm red and yellows on one end, to the cooler blue and violets on the other. The color perceived by the human eye is simply an interpretation of the wavelength of that light. Sunlight also contains plenty of “invisible” light, including infrared and ultraviolet light (not really light at all, since its not visible). Artificial light, on the other hand, does not contain the full spectrum of wavelengths and has disproportionate amounts of certain wavelengths, most notably the blue/green spectrum from 400-550nm wavelengths.
So how does light exposure impact biology? We have receptors in our eyes and skin that actually sense the wavelength of light and send neuro-hormonal signals through the body to generate a response. One of the best studied of these is the relationship between blue light and melatonin. In the morning, blue light from the sun signals the brain to stop production of melatonin, a hormone that promotes wakefulness. Likewise, after sundown, the natural absence of blue light stimulates natural melatonin secretion and promotes sleep.
You don’t have to think long and hard about how this might be screwed up in our lives today. Few people wake up with the sun–they either sleep in or are rattled awake by an alarm clock prior to sunrise. They hop on their smartphone, watch TV, or rush to work where they are subjected to artificial light all day, and return home to relax in front of a TV or computer emanating blue light well past sundown.
Blue light is all around us at virtually all times. In fact, as your read this on your smartphone or computer, your eyes are being bombarded by predominantly blue and green spectrum light. Excessive blue light can do more than impact sleep–its been shown in studies to induce weight gain and a pre-diabetic state and may contribute to cardiovascular disease. Blue light is not inherently bad, we just get far too much of it at the wrong times. The dose makes the poison.
Fortunately, there’s an antidote. and its a bit easier to swallow than getting rid of all LED screen and lights. Yep–I’m talking about those dorky glasses we’re wearing in the picture above. Blue blocking glasses have been around for years, but have experienced a major resurgence as awareness surrounding the damaging effects of excessive blue light grows. We started wearing Felix Grays with sleep lens in the evenings several months ago and have noted excellent results with sleep quality. They aren’t too pricey, they look good, and their lens technology reduces blue light without the crazy yellow/orange tint you find on other products (so color change when watching TV is really not that noticeable…and you don’t look like a total weirdo). Some people report that wearing blue blocking lens reduces anxiety, stress and even migraine headaches. I’ve begun wearing blue light reducing clear lens glasses during the day at work since I’m standing in front of a computer monitor almost half the day, and it seems to help reduce eye strain and fatigue.
Light exposure is an underappreciated component of health and wellness. Management of blue light is the first place to start, but its not the only aspect of light exposure worth exploring. In the next post, we’ll look at exposure to the other end of the spectrum–red light–and examine the benefits and drawbacks of the “invisible” spectrums of UV and IR light.