5 Main Sources of Blue Light and How to Limit Blue Light Exposure
Blue light is a naturally-occurring part of full-spectrum sunlight, but it’s also isolated and used to illuminate our screens and light bulbs. Artificial blue light is extremely bright, and that can have negative effects on sleep and eyes if you take in too much. So where does all that blue light come from? In this article, we’ll break down the 5 most common sources of blue light exposure. We’ll also explain some of the health effects of blue light, and suggest ways to cut down on harmful blue light exposure.
Life on earth runs on the light and energy we receive from the sun. Natural sunlight is full-spectrum light. The full spectrum of light (also called the electromagnetic spectrum) includes numerous wavelengths and colors, like red light (in the mid-600s nm range) and blue light (in the 380-500nm range).
When blue light is combined with other colors and wavelengths in natural sunlight, it doesn’t pose the same risks as when bright blue light is isolated for technological purposes.  Humans have evolved to thrive with full-spectrum sunlight, and when we get blue light along with the other wavelength from the sun, it can even have positive effects, like regulating our circadian rhythms and long-lasting eye health. [1,2] You can learn more about sunlight and wavelengths in this Overview of Light.
What Can you Do? Get outside! Taking in natural, daytime light has lots health benefits for sleep, skin, mood, and a lot more.  Full spectrum light, with blue, red, NIR, UV, and other wavelengths helps your body and cells stay in balance.
Artificial Lighting in Your Home
The common fluorescent and LED lighting in your home uses blue light that’s been isolated from the full light spectrum. Artificial blue light is very bright, which is great for lighting a building in a cost-effective way. Blue light works well for illumination, but all that blue light exposure can also affect your sleep and circadian rhythms. Our brains interpret light as a sign of when to be asleep and awake. An overload of bright blue light at night can actually prevent your brain from making proper levels of melatonin and other sleep hormones that help you fall asleep and stay asleep.  You can learn more about light and sleep here.
What Can you do? Artificial lighting is a necessity of modern life, but try to avoid excessive use, especially later at night. That’s when excess blue light exposure is the most detrimental, because of the potential to disrupt your sleep and circadian rhythms. Joovv’s new Ambient mode was designed for less intense lighting at night. Now you can use your Joovv setup to light your home in the evenings, with softer red light that will help your body wind down and sleep.
What’s on TV tonight? Blue light! Almost every television uses intensely bright blue light to illuminate the screen and bring the picture to life.  The longer you watch TV, the more you’re basking in artificial blue light. Like artificial lighting, this is mainly a problem at night, when your brain and body are winding down to sleep. Taking in too much TV light can interfere with your sleep and circadian rhythm.  It can also lead to eye strain and headaches. 
What Can You Do? The best way to avoid the downsides of TV light is to turn it off at least an hour before bed. Give your body time to transition into sleep without all the blue light in your face. It’s also best to limit the late night TV binging. Try a book instead. Reading has been found to decrease blood pressure, lower heart rate, and reduce stress. 
Americans spend A LOT of time on computers these days, and that’s not changing anytime soon. Like TVs, computers use bright blue light in their screens, and that can mess with your eyes and sleep if you take in too much.
What Can You Do? Aside from limiting screen time (easier said than done), you can turn your screen brightness down, and use blue light blocking filters for your computer screen. There are plenty of apps designed to reduce the color temperature of computer screens too. Some of them use your location and sync with your local light/dark cycle to change your screen brightness gradually throughout the day. You won’t notice, but your eyes and brain can feel the difference, especially when it’s time to sleep.
Phones and Tablets
Phones and tablets are small computers, and they have the same blue-lit screens that beam bright light at us at any time of day. We use them all the time, but looking at your phone for too long at night can sabotage your sleep.
Phones and tablets can be a bigger blue light risk than TVs and computers simply because there’s less distance between our eyes and the screen. Less distance means less light diffusion, so we’re taking in a more concentrated blast of blue light every time we read a text or check an app.
What Can You Do? Like computers, there are apps and filters to lower color temperature and block blue light. Setting personal limits for screen time can help, like trying not to use your phone in bed at night. Some people also like blue blocking glasses that filter blue light from screens and artificial lighting. The key is to avoid staring at your phone in the hour or two before you try to go to sleep. And if you’re having trouble sleeping, rolling over and looking at your bright phone is a surefire way to stay awake.
Conclusion: Blue Light is Unavoidable, But You Can Limit Your Exposure
You’re going to use phones, computers, TVs, and artificial lighting. They all bring a lot of bright blue light into your life. But if you use them less at night and before bed, you can minimize the negative effects on your sleep and circadian rhythm. Getting outside during the day and getting natural, full-spectrum light is a big positive for your health & sleep, and counteracts some of the effects of excess blue light. To learn more about blue light and how to limit your exposure, check out this article.
Sources and References:
 Dan Roberts. Artificial Lighting and the Blue Light Hazard (The Facts About Lighting and Vision).
 Williams KM, Bentham GCG, Young IS, et al. Association Between Myopia, Ultraviolet B Radiation Exposure, Serum Vitamin D Concentrations, and Genetic Polymorphisms in Vitamin D Metabolic Pathways in a Multicountry European Study. JAMA Ophthalmol. 2017.
 Mead MN. Benefits of sunlight: a bright spot for human health. Environ Health Perspect. 2008 Apr.
 Jung C, Khalsa S, et al. Acute Effects of Bright Light Exposure on Cortisol Levels. Journal of Biological Rhythms. 2010 Jun.
 Harvard Health. Blue light has a dark side.
 Can Reading Reduce Stress? World Literary Foundation.