Blue Light: The Double-Edged Sword

Trevor Hess
Nov 15, 2020
6 min read

Updated: Nov 22, 2020

Ah yes… blue light. It's all around us and is inherently fundamental to our biology just as it's always been dating back to our early ancestors. However, in the world we live in, too much of anything can be problematic, and this couldn't be more true than with the case of blue light.

Stepping back, our ancestors were exposed to blue light daily, just as we are today. However, there's a drastic difference in the amounts of blue light we are exposed to today as compared to what our ancestors got on a daily basis. Could you guess where our ancestors got their blue light? Yup, that's right, the sun. Notice I said they were exposed to blue light daily, not nightly, not all day — just daily.

Now think about the sources of blue light today. Well, the sun for starters, but also electronics like phones and computers, household appliances like microwaves and ovens, as well as indoor lighting, billboard signs, traffic lights, car lights, and the list goes on.

Regardless, blue light is vital for our health — period. However, in today's day and age, we've gotten to a point where blue light is so accessible that unless we take active measures to optimize the amount of it we get each day, it can become rather detrimental to our health. So that's exactly what I want to do in this article — run through the most influential ways blue light affects us and how to optimize each.

1. Circadian Rhythm

The human body is unique in the fact that many of our biological processes run on a circadian rhythm, which means our body performs different physiological processes based on the time of day.

For example, a typical circadian rhythm looks like the this:

2:00 AM: Deepest Sleep
4:00 AM: Lowest Body Temperature
6:45 AM: Sharpest Blood Pressure Rise
7:30 AM: Melatonin Secretion Stops
10:00 AM: Highest Alertness
2:30 PM: Best Coordination
3:30PM: Fastest Reaction Time
5:00 PM: Greatest Cardiovascular Efficiency and Muscle Strength
6:30 PM: Highest Blood Pressure
7:00 PM: Highest Body Temperature
9:00PM: Melatonin Secretion Starts

As you can see, there's quite a lot of bodily functions that are correlated to our circadian rhythm. However, blue light is a big player when it comes to maintaining the timing of our circadian rhythm. How does it do this? — by cuing daytime and nighttime.

What do I mean by this? Our body relies on the presence of blue light, or lack thereof, to make the final decision as to whether it's daytime or nighttime internally. If the body senses a lack of blue light, it's a cue to start performing bodily functions associated with nighttime, such as the secretion of melatonin, which is vital for sleep. On the flip side, if the body senses the presence of blue light, it's a cue to start performing bodily functions associated with daytime, such as increasing blood pressure and body temperature for alertness.

How does our body sense blue light anyways? — two primary ways: through the use of photoreceptors in our eyes and on our skin. Our skin? Yep, it's surprising, but even if our eyes aren't exposed to light, our circadian rhythm can still be impacted simply by light interacting with our skin.

So what can we do to make sure our body is properly sensing whether it's daytime or nighttime? Simple — completely eliminate blue light at night and expose yourself to blue light during the day.

Well… not so simple. It was simple for our ancestors, but like I said, we are exposed to so much blue light nowadays that we need to take matters into our own hands.

As a result, here's the best strategies I've found for doing just that:

Wear blue light blocking glasses at least 2 hour prior to bedtime. By doing so, you'll prevent your eyes from sensing any unwanted blue light before getting ready to fall asleep. I think Ra Optics are the best choice since they not only block blue light, but also green light, which can be stimulating as well.
Use the red light trick on your iPhone to eliminate most of the blue light from your screen. Electronics emit unappreciable amounts of blue light whether it's daytime or nighttime, so for nighttime, it's best to eliminate as much of it as you can.
Utilize a comfortable sleep mask to completely eliminate all light while you're sleeping. Once you take off those glasses, you surely don't want any light from your sleep environment to keep you up, whether it be from electronics or even the moon.
Utilize blackout curtains and turn off all electronics to eliminate all light in your sleep environment. It's best to eliminate as much blue light from your sleep environment as possible since, like I said, even if you can't see it, your skin has photoreceptors too.
Utilize circadian rhythm light bulbs to mimic the timing of light in nature within your own home. The more closely you mimic the pattern of light our ancestors experienced, the easier it'll be to maintain your circadian rhythm.
Get sunlight first thing in the morning. By doing so, you'll cue your circadian rhythm to start all over, which will subsequently improve your sleep later that day.

2. Vitamin D Production

Just like it's important to optimize blue light exposure to maintain a healthy circadian rhythm, it's just as important for maintaining healthy vitamin D levels. Vitamin D, specifically vitamin D3, is one of the most important vitamins for our overall health, which you could've probably guessed since it's produced by the body. Regardless, the major benefits of vitamin D include:

Regulating the absorption of calcium and phosphorous for growth as well as bone health
Facilitating normal immune function to build resistance to diseases
Reducing inflammation
Modulating glucose metabolism

Although you can get some vitamin D from foods such as oily fish, liver, and egg yolks, the best source of vitamin D is the source your own body produces when exposed to sunlight. When the sun rays, specifically the UV-B rays, hit our skin, they actually interact with cholesterols within the skin, resulting in the production of energy required for vitamin D synthesis to occur.

However, in today's day and age, it can be more difficult to get enough of the beneficial blue light from the sun that we need. Whether that be due to the fact that everyone's staying indoors more often because of the current COVID-19 pandemic and subsequently having to work remotely, or due to the fact that in the northern states, winter's creeping up on us, so sunlight is simply not as accessible this time of year.

Regardless of the circumstance, the two best strategies I've found for optimizing your vitamin D levels include:

Going for at least a 15-minute walk in the sunshine. Preferably go for a walk when the sun is at its peak, as this is the best time to get your blue light.
Invest in a Sperti Vitamin D Sunlamp. If sunshine is limited, utilizing a UV-B lamp is a great way to still make sure your getting enough of the beneficial rays — but not too much.

3. Eye Health

Finally, just like how blue light is necessary for maintaining our circadian rhythm and vitamin D levels, it's also necessary for boosting alertness, helping with memory and cognitive function, as well as elevating mood throughout the day. Unfortunately, too much blue light exposure nowadays, specifically unnatural blue light exposure, is becoming rather detrimental to the health of our eyes. Why do you think it's so hard to look directly at the sun? — the blue light. Now, to a lesser extreme is the blue light emitted by electronics. However, just like the sun, we weren't meant to stare directly at these light sources.

Regardless of the source, too much blue light exposure to the eyes can cause a whole host of problems including:

Retinal Damage
Macular Degeneration
Cataracts
Blindness

So yea, first and foremost, don't look directly at the sun… that's a no-brainer. However, it's kind of hard not to look at your electronics while you use them. As a result, just like with our circadian rhythm, we again have to take matters into our own hands.

Here's the best strategies I've found for managing blue light from electronics:

Use blue light blocking screen protectors for your electronics. This is probably the easiest way to limit blue light since once the screen protectors are installed, you don't have to think about it.
Install Iris Software on your devices. This software not only reduces blue light, but also reduces the flickering of the LEDs, which can be harmful for the eyes as well.
Keep your iPhone on "Night Shift" mode to reduce the blue light. There's just no need to have all that blue light 24-7 if you can do something about it.
Use yellow-tinted blue light blocking glasses. It's great to use yellow-tinted blue light blocking glasses during the day for computer work so as to protect your eyes, without completely eliminating all the blue light like you would when using the red-tinted styles for sleep.

Summary

So there you have it! As you can see, blue light can be both beneficial and harmful. We so desperately need it to maintain a healthy circadian rhythm and vitamin D levels. However, with all the excess blue light in today's day and age, or even lack thereof in some cases, it's important to implement strategies to manage the amount of blue light we get in order to optimize our health. All the strategies mentioned are a great place to start, and like I said in my previous article, beneficial or deleterious habits have a compounding effect in either direction. So the more of these habits you implement, the better!

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