Why should we be interested in blue blockers? More than a century ago now, at Menlo Park in California, a certain Mr Thomas Edison invented and marketed the light bulb. The change that this relatively simple invention has wrought upon the World has been enormous. At a stroke, night was turned into day. Now there is barely a household on the planet that does not have their circadian rhythms disrupted by the glare of constant light. Night and day have been abolished, allowing us to work through the entire period.
One of the major casualties of this change has been the quality of our sleep. For literally millions of years beforehand, human beings and their precursors were ruled by the sun. Our internal rhythms dictated by the rising and the falling of our nearest star on a daily basis. For the most part, we slept when our circadian rhythm said we should sleep and woke when it said we should awaken. This is no longer the case. And this is where blue blockers come in.
What are Circadian Rhythms?
Circadian rhythms can be thought of as analogous to internal clocks that rule over the rhythmicity of our lives. They tell us when to sleep, when to wake, when to be alert, when to relax. These rhythms run on a near 24-hour cycle, following a single rotation of the Earth as our planet slowly rotates around the sun. The term itself comes from the latin ‘circa’ for around or about, and ‘diem’ for day.
The actual mechanism governing the circadian rhythm is to be found in the suprachiasmatic nucleus at the centre of the brain in the hypothalamus. It works through its relationship with light. The light coming in through the eyes activates IpRGCs (Intrinsically photoactive Retinal Ganglion Cells) and signals to us the time of day and season, grounding us in the rhythms of our planet.
Cortisol and Melatonin
Disruption of our circadian rhythm can affect us in all manner of ways, not the least of which is the sleep-wake cycle. It does this through its effect on various hormones. Chief amongst these are cortisol and melatonin. Cortisol is sometimes referred to as the ‘stress hormone’. This seems more than a tad unfair. We need cortisol to wake us up and to be alert. Conversely, melatonin helps to relax our bodies and prepares us for the coming night’s sleep. Wearing blue blockers at the appropriate time of day will help our bodies produce the melatonin needed to ensure the slumber we need.
The modern world, with its artificial lights, its TVs and computers, its smartphones and its 24-hour shopping, seems to be at war with the natural rhythms within us. As in so many other matters, we seem to feel that we can safely ignore several million years of evolution and simply play fast and loose with our sleeping patterns.
We do so at our peril.
Many people suffer at least some degree of sleep disruption in this day and age. They live lives that are constantly out of sync with their natural rhythms. Shift workers, computer gamers, ‘night owls’, and workaholics, all seem to live under the delusion that they can be heedless of their own internal rhythms.
You hear folks say things like ‘there’ll be time enough for sleeping when I’m dead’, often not realising that they are accelerating that day by following such arhythmic lifestyles. Disrupted sleep robs us of energy, of the ability to concentrate, and can lead to depression and other psychological maladies. Being deprived of sleep can, in simple terms, take all the fun out of life as we struggle to get through the day feeling lacklustre and tired.
What is Blue Light?
Blue light is part of the visible light spectrum. This ranges from ultraviolet to infrared and from 400 to 800 nanometres in wavelength. Blue light is the part of the spectrum that signals to our eyes, and hence on to the suprachiasmatic nucleus, that it is daytime. This will cause the release of the hormone cortisol and thereby increase our degree of alertness.
Within our eyes, the photopigment melanopsin is primarily activated by the shorter wavelengths of the visible spectrum. The most significant activation is made by blue light; that is the wavelength of light found between 420 nm and 480 nm.
Blue Light is Everywhere
The problem in the modern world is that electric lights, computer screens, smartphones, and televisions all emit the blue light that signals to our brains that it is daytime, hence that we should be awake and alert. Simultaneously, the blue light will also cause the suppression of the production of melatonin, our sleep hormone.
Because of the ubiquitous nature of blue night these days, our circadian rhythm can become confused. Thus, in the evening when we would wish to be winding down towards sleep, staring at blue light-emitting screens, or even simply being under bright lights, will be keeping us awake and alert.
Eventually, if and when we do sleep, the quality of that sleep will be much worse. We will then be more tired, moodier, and more prone to depression the next day and those following. Simply put, we will be less alive, less healthy, less vital.
How do Blue Blockers Work?
Blue blockers are a form of spectacles that seeks to block out the blue light in our surroundings. Clearly, we would only want to do that in the part of the day where the blue light will threaten the quality of our sleep; ie the evening. For the rest of the day, it is not a great problem if we are wide awake. In fact, most of us would wish to be for the most part.
Some guidance from our past
Historically, for the past few million years, blue light would naturally reduce after sunset. As the blue light reduced, our bodies would be receiving signals to increase the production of melatonin in preparation for the coming period of sleep. From the time of Mr Edison’s dangerous invention onwards, however, these previously clear signals have become more and more confused.
As with our diets, and as much as many rile against it, the reality is that we are embedded in our species’ history. It takes many millennia to make adjustments through evolution. At base, despite all the changes that the modern world has wrought, we are still essentially the same as our hunter-gatherer ancestors that roamed the planet 20,000 years ago.
What can we do about it?
To address this problem we need to find ways to reduce the amount of blue light we perceive in the evenings. Blue blockers are, as the name suggests, glasses that are specially designed to filter out blue light. The absence of blue light will then help to indicate to our brains that it is time to increase the production of melatonin in readiness for sleep. As the pineal gland increases melatonin production, we will feel sleepier and sleepier.
Using blue-blocking glasses to protect us from the negative effects of blue light at the wrong time of day is a relatively new development. The studies that have been done so far do seem to confirm the usefulness of these devices, however (1), (2).
Which Blue Blockers to Choose
There is a wide range of possibilities here. One can go for the theoretically latest and greatest blue-blocking spectacles and pay a few hundred pounds for the privilege. Conversely, you can get a relatively cheap pair for just a few dollars that are likely to be equally effective. As these are something you only will need to use for an hour or two a day, and mostly in your own home, I would go for the more economic end of the spectrum.
The pair of glasses I personally chose were relatively cheap, wrap-around, and effective at blocking out the shorter wavelengths of visual light (if you recall, the blue light ranging from 420 nm to 480 nm in length) that we require.
Another potential complication here is that many of us may require corrected lenses to allow us to see clearly. There are two solutions to this problem. The first, and more expensive, is to buy a pair of prescription blue-light blocking glasses. The second, and more economic way to go, is to purchase some blue-light blocking clip ons. Again, as the necessity for wearing these is limited to just an hour or two a day, I would go for the latter solution.
Beyond solutions that we can purchase, there is a whole range of practical measures we can take that cost absolutely nothing. These solutions will generally be highly effective but do require a certain amount of discipline. You pays your money (or not) and takes your choice.
Reducing Exposure to Blue Light
This is perhaps startlingly obvious but may need stating nevertheless. If you simply don’t use blue-light emitting screens for a couple of hours before bedtime you will have achieved the desired effect. Instead of staring at screens, a book could be read (a real book with paper pages …) or a podcast or radio could be listened to. In extremis, we could even share a conversation …
This still leaves light coming from electric lights, of course. This problem can be solved by buying appropriate light bulbs that emit light from the redder end of the spectrum.
Adjusting Electronic Devices
In practice, it is better to avoid screens later in the evening whenever possible. Given their ubiquity, however, quite a few of us would struggle with this. If this is the case, then some devices do have useful options in this regard. Many modern operating systems on phones and laptops allow us to set them up in such a way as to become more red oriented as the day goes on. Combined with this, I would also suggest simply turning the brightness down to the minimum usable level.
Avoid Caffeinated Drinks
Coffee and other caffeinated drinks are very useful for keeping us wide awake. They even help promote ketosis at some levels (3). On the other hand, they are not the ideal drinks if one wishes to enjoy a good nights sleep. Like blue light, they have a tendency to elicit a response from the hormone cortisol. This is fine at 9 in the morning, but perhaps not so good at 9 in the evening. Personally, these days at least, I tend to keep my coffee drinking to the mornings, much as I enjoy the occasional Americano.
Keep the Noise Down
We respond to noise, especially unexpected or surprising noises. This is probably a survival mechanism that goes way back in human history. If we are attempting to wind down at the end of a long day though, loud or surprising noise is the last thing we need.
Adopt Regular Hours
As much as we like to think of ourselves as exciting and unpredictable characters, our bodies often prefer the exact opposite. Circadian rhythms are just one example of the fundamental regularity that is built into us as humans. Others that also have a profound effect on us are diurnal, ultradian, and infradian rhythms. Such rhythms pulse through every cell of our bodies.
We will tend to thrive in as much as we can keep our daily rhythms relatively constant. Getting up at around the same time every day, sleeping at around the same time. Even meal times should ideally be kept reasonably constant. Your body will quickly adapt to such regularity and ready itself appropriately.
Apologies if following such routines sounds just a tad boring, but I assure you the rewards you will reap in terms of wellness, health and simply feeling more alive will make the small sacrifices required more than worth the effort (4).
The quality of our sleep is vital to the quality of our lives. It is dependent, at least to some extent, on our body’s response to its own internal rhythms. These are dictated by the production of hormones that signal to us when it is appropriate to be awake or asleep. Living in concert with these rhythms plays an important role in the quality of our sleep, hence in the quality of our lives. Being awake in the middle of the night is as detrimental as being tired in the middle of the day. Blue blockers, along with changes in lifestyle, help us to solve this modern-day problem and may ensure that we can, once again, enjoy a comfortable, deep, and refreshing night’s sleep.