Blue light is something we all encounter every day, all around us. While you’ve probably heard the term blue light and might even own a pair of blue light-blocking glasses, but what exactly is it? What does it do? How does it affect your sleep, work, and general wellness?
What is blue light?
Blue light is a natural part of the visible light spectrum meaning it can be seen by human eyes. It’s opposite of warmer wavelengths like red and yellow. It emits short, high-energy wavelengths between 415 and 455 nanometers, whereas warmer waves are slower. Short waves may help keep you awake and focused during the day and warmer waves, especially red, signal to your brain that it’s time for sleep. (Blue light is also the reason why we see the sky as blue!)
We encounter blue light primarily via the sun, but it’s also emitted from fluorescent light bulbs, LED lighting, and digital devices like smartphones, computers, and tablets.
What does blue light do?
During the day, blue light can promote feelings of alertness and helps us regulate our natural circadian rhythms. Before the invention of electricity, natural blue light via the sun was how people knew it was time to wake up, and when the sun went down, it was time for bed.
The negative effects of blue light
There’s no denying that we live in a digital world. We are now surrounded by artificial blue light all the time, whether that’s via our smartphones and tablets or energy-efficient LED lighting.
The CDC reports that nearly 70% of children 12-15 years old spent more than the recommended two hours of screen time each day. Teens, of course, are constantly connected to devices for their social lives and schoolwork, and so are adults, especially as so many careers require many hours at the computer.
While the long-term effects of blue light are still being studied, Harvard Health Publishing reports that blue light may disrupt our natural circadian rhythms and make it more difficult to fall and stay asleep. It can also impact the secretion of the hormone melatonin, which signals your body that it’s time for bed. If you have children, you know how vital a good night’s sleep is for their overall well-being – and you need your quality sleep too!
How do our eyes filter blue light?
It’s all about carotenoids, specifically lutein and zeaxanthin. Carotenoids are pigments found in fruits and vegetables; your body doesn’t produce these naturally. You can incorporate lutein and zeaxanthin into your diet with foods like carrots, kale, broccoli, and spinach, though the American Optometric Association notes that the typical Western diet is low in carotenoids.
Lutein and zeaxanthin are stored in your eyes — specifically in the macula, the region of the eye near the center of your retina that helps you focus on what’s in front of you, like a computer screen or notebook.
Maculae are exposed to a great deal of blue light throughout the day, but these key carotenoids work as a filter to help reduce the intensity of blue light that reaches the retina. Increasing your intake of lutein and zeaxanthin can increase macular pigment levels in the eye, which helps build a stronger filter against blue light.1 Studies have shown that lutein and zeaxanthin also have antioxidant properties and may support other eye health benefits.2,3
Tips to reduce exposure to blue light
Consider enforcing a “no devices” rule at least an hour before bedtime and require family members leave phones and tablets outside their bedroom at night. If you’re using screens at night for work or homework, dim screens or switch to night mode to reduce blue light exposure that may impact your sleep.
Opt for warmer-toned LED bulbs in your home to reduce blue light exposure.
If you’re on a computer or device throughout most of the day, make sure to take tech breaks if possible. Try the 20-20-20 rule: every 20 minutes, shift your eyes to look at an object 20 feet away for at least 20 seconds. Get up and go for a short walk around the block to get your steps in and give your eyes a break.
Be sure that everyone in your family wears sunglasses when they’re out and about in the sunshine because the sun is another source of blue light. (The sun is also present under cloud cover, so keep sunglasses in your bag and car for those partly cloudy days.)
Blue light may be all around us, but with a few small tweaks to your existing routines, you can reduce your family’s exposure and keep your eyes on the prize.