Blue Light: The Whole Story

What is Blue Light?

 I’m sure you’ve heard the term circling the internet and the media, but there’s a lot of existing hype around what it is, and what it isn’t. Let’s start with a few basics.

Blue Light Basics:

It’s fairly basic knowledge that the human eye contains two types of cells: rods and cones. These devices are present in your retina and they are the optical light receptors. The three types of cones pick up on blue, green, and red light, in turn creating what we know as color vision. The rods, on the other hand, do not sense any color, and they are used in your eye for low light level situations. 

To pick up on light, which allows us to see, rods make use of a protein called rhodopsin. The molecule retinal, which is also able to detect and absorb light, lives inside of this protein. Signals are sent through the optic nerves from your eyes to your brain when this specific molecule detects light. However, studies from the University of Toledo show that when retinal is exposed to excessive blue light, a specific kind of  the cells are killed. Compounds exist in our body to protect these cells and counteract the effects of blue light, but retinal exists in more places within the body than just the eyes. Blue light could be more harmful and toxic to our whole bodies than previously thought. So again, what is it?   

Light, as we know it, exists in the full color spectrum, with wavelengths ranging from extremely red to extremely blue. Red wavelengths being the longest type and blue wavelengths being the shortest. The longer wavelengths carry a lower amount of energy, and the shorter wavelengths pack in a lot more. Blue light is all around us. It’s not wholly a negative thing for us to take on blue light. Blue light boosts our mood, and our focus and attention span. We need a certain amount of blue light to keep our bodies running smoothly. 

Where do we get it? 

Our sun is actually a major source of blue light. The sun provides Vitamin D, which we need to survive. It’s important for us to receive this daily exposure to blue light to keep our bodies running. When we aren’t being exposed to blue light from the sun, though, we take it on it a lot of other ways. Our modern media devices and screens are rife with blue light. Televisions, mobile phones, computer monitors, and a myriad of other devices all are sources of raw blue light. The problems begin to manifest themselves when our bodies are exposed to an irregular amount of blue light. 

Why is it good, and bad?

As stated earlier, we need a certain amount of blue light to keep our bodies going each day. It’s best to receive the light during daytime hours from the sun, especially during the morning and the early afternoon. By doing this, we increase alertness during the daytime, meaning we won’t be feeling sleepy when we shouldn’t. A natural amount of exposure speeds up our reaction times and helps our attention span become stronger, as well. 

What is considered a “regular,” or “natural” amount of blue light? Studies show that prolonged exposure isn’t a necessity to receive the needed benefits. As little as 30 minutes of blue light admitted in the morning hours caused quicker reaction times and increased memory capacity for those involved. 

The invention of electric light brought a higher volume of blue wavelengths into our lives. Now, when our main source of blue light sinks below the horizon in the evening, we are still being exposed to the same, if not larger, amount of blue light. We are sitting beneath our energy efficient lightbulbs as the blue light from our phone screen shines into our retinas and onto our thyroid glands, while the TV playing in front of us casts blue light onto our faces and bodies. You may not have thought about it like this before, but does this scene sound familiar? Billions of people participate in these routines each night, and they have no idea how it might be affecting their health. 

Light exposure has an enormous effect on our sleep cycles. When we’re not getting enough sleep, or too much, it directly affects our performance, our mental state, and our behavior. In fact, studies have shown that many direct, and indirect connections exist between light and our mood alone. It also affects our natural rhythms, melatonin production, and has even been linked to depression and other mental health issues.

Light and Sleep

If you are a normally functioning human being with no extenuating circumstances, you probably go to bed and wake up around the same time each morning and evening, save a little leeway for late movie nights and early morning sunrises. This is what is called a circadian rhythm. Circadian rhythms are our internal clocks that dictate when we wake up and when we go to sleep. Normal cycles for our sleep/wake schedules fall around the 24 hour time span. Our circadian rhythm also dictates our behaviour, hormone secretion, cellular function, and gene expression. The cycle responds primarily to processed light and darkness in our environment. http://www.mentalhealthamerica.net/blog/how-blue-light-affects-mental-health

Naturally, then, it makes sense that an excess amount of blue light would disrupt these rhythms. In fact, more than you might think. After excess exposure to this light, our bodies will not be producing melatonin at capacity. This means we will not be achieving the amount of restful sleep we need. We’ll wake up more throughout the night, and we won’t gain the required amount of REM sleep. This means our brain loses the opportunity during the night to facilitate tissue growth, muscle repair, and a multitude of other processes. Not only that, but sleep disruption is also a “classic symptom of major depression, bipolar disorder, post-traumatic stress disorder, generalized anxiety and other mood disorders. Likewise, it is one of the most obvious likely consequences of exposure to nighttime lighting.” http://www.mentalhealthamerica.net/blog/how-blue-light-affects-mental-health

Light and Depression

When looking at how light exposure can affect mood and mood disorders, it’s important to look at the indirect links rather than solely the obvious ones. Earlier, it was stated that our circadian rhythm dictates behaviour, hormone secretion, cellular function, and gene expression. The systems that are disrupted by light (an indirect link) in our bodies are sleep, neurotransmission, gene expression, and hormone secretion. Are you starting to see the connection? Basically, if we aren’t getting the rest we need to keep our circadian rhythm in line, it’s going to throw off a lot of other processes going on. 

Sleep disruption is really the root effect of this issue. When a close look is taken at the top symptoms of clinical depression, bipolar disorder, post-traumatic stress disorder, and generalized anxiety, disrupted sleep is at the forefront. Studies have shown that blue light directly inhibits melatonin production, melatonin being the hormone produced by the body that’s responsible for restful sleep. When blue light exposure grows out of control and the circadian cycle in the body is disturbed, mood disorders can manifest altogether or worsen greatly. It’s safe to say, then, that sleep is important. Human will spend a third of their lifetime sleeping. It’s a pretty big deal to make sure it’s happening the right way, or happening at all. 

It’s essential to note, in these situations, that light is not an enemy. Light is incredibly beneficial and we need it to survive, provided we receive the correct amount of exposure in the correct situations. In fact, light has actually been proven to be an incredibly effective tool used in the treatment of depression and other mood disorders, especially Seasonal Affective Disorder, or SAD. Studies have shown that even just 30-60 minutes of exposure daily to artificial light, especially blue light, can have a significant effect on mood, especially during the winter months when sunlight is not as abundant during the day. The sun is a blue light, so you are receiving essentially the same effects as being outside in the sunlight. Keep in mind, however, that this is not a replacement for sunlight. It is very important to receive at least a small amount of exposure to natural morning or afternoon sunlight to keep body processes running properly. 

Conclusion

For thousands of years, what humans did during the day was dictated by the cycles of the sun and the moon. Save fire, and the moon, after the sun went down in the evening there was no source of light, and people went to sleep. People have not always spent the majority of their day inside an office. Negativity surrounding blue light seems like a relatively new concept, and that’s because it is. The technology that now dictates our lives (smartphones) did not even exist twenty years ago. Our entire world has changed in such a short amount of time, and it only makes sense that our bodies and needs would change as a result of that as well. It’s important to be mindful of what has taken place, and adapt our bodies and our routines to this changing world. Begin making small changes now to monitor your blue light intake, and your body will thank you later.