Is blue light from devices bad from you? Here’s the truth…blue wavelengths are beneficial during daylight hours because they can boost attention, mood and our reaction times, but are unfortunately disruptive to our circadian rhythms at night and impair our ability to sleep.
Why Sleep is So Important
Having adequate sleep and not putting out circadian rhythms out of whack is a key ingredient to our health, with numerous studies showing that people who fail to get adequate sleep do so at a cost, including excess calorie intake after dinner, lower levels of energy, weight gain, and some impacts to how the body uses insulin. While there is still room for research to tie the impact of lack of sleep to chronic medical conditions like diabetes, some recent research seems to show this causal relationship to exist.
For example, a recent Harvard study put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.
Some More Interesting Findings About Blue Light
Exposure to light can influence circadian rhythms and is one of the reasons people don’t get enough sleep, according to Stephen Lockley, a Harvard sleep researcher. Of all the types of light, blue light seems to be the most egregious. Blue light makes up the highest energy portion of the visible light specrum. In another study conducted by Harvard researchers, an experiment was conducted that compared 6.5 hours of exposure to blue light vs green light at a comparable brightness and blue light was found to suppress melatonin for close to twice as long as green light and shifted circadian rhythms by twice as much.
There is a visual neuroscientist who has spent the last 2 decades investigating the way our visual system detects and responds to light. Inspired by a curiosity in cuttlefish and how their vision works, he learned that the mechanism we use to perceive polarized light is caused by molecular components in the retina that protect our eyes from blue wavelength light. From this research, she found that the exposure to blue light matters more than intensity.
Another interesting study showed that our own natural, internal protection against blue light and macular pigmentation is essential to protecting against age-related macular degeneration. In another study that looked at 15 sisters at the Benedictine monastery on the Island of Rab found that these sisters who lived in the very dark monastery had retinas of much younger patients despite being considerably older, average age in their 60s. Further, the only two sisters who had shown macular degeneration were the ones responsible for gardening and had spent significant time outside!
So what can you do about it?
- Use dim lights at night
- Avoid looking at bright screens 2-3 hours before bed or if you do, wear blue-blocking glasses or turning on night mode on your phone
- Expose yourself to lots of bright light during the day (be sure to wear sunscreen) which will help boost your ability to sleep at night
- If you do buy blue light protection eyewear, make sure they adhere to the International Organization for Standardization (ISO) standard which recommends protection for specific blue light in the ranges of 380 to 455 nm to lower the risk of retinal damage
- Eat dark leafy greens and brightly colored fruits and vegetables which are full of carotenoids which support macular pigmentation. Macular pigments can block up to 80 percent of blue light from the retina.
How to Turn on Night Mode on Your Phone or Laptop
Note in each of these settings there is generally an ability to schedule when these settings are applied so you don’t have to remember to do it every night. Something to consider to make this process more convenient for you.
iPhone/iPad
- Go to Settings à Display & Brightness
- Tap the Night Shift setting, which alters the screen temperature of your device to a warmer color, filtering out blue light
Android
(Note this varies some between the different flavors of Android devices)
- Go to Settings à Display
- Look for an option called Night Light or Blue Light and turn it on
Windows 10
- Go to Settings à System à Display
- Toggle the Night Light switch to turn on the feature
Sources
“Blue light has a dark side”, Harvard Health, July 07, 2020 https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side
“What Science Says About Blue-Light-Blocking Glasses”, Leslie Nemo, December 10, 2020, https://www.discovermagazine.com/health/what-science-says-about-blue-light-blocking-glasses
“How to Stop Blue Light From Disturbing Your Sleep”, Lance Whitney, February 3, 2021, https://www.pcmag.com/how-to/how-to-stop-blue-light-from-disturbing-your-sleep#:~:text=On%20your%20iPhone%20or%20iPad%2C%20go%20to%20Settings%20%3E%20Display%20%26,filtering%20out%20the%20blue%20light.
“What we know about blue light science and research in 2020”, Jennifer Lyerly, OD, February 26, 2020, https://www.optometrytimes.com/view/what-we-know-about-blue-light-science-and-research-2020
El-Sayed M. Abdel-Aal, Humayoun Akhtar, Khalid Zaheer, and Rashida Ali. Dietary sources of lutein and zeaxanthin carotenoids and their role in eye health. Nutrients. 2013 Apr; 5(4): 1169–1185. “Stop blaming blue light for all your problems. It’s not quite the enemy”, Alex Schwartz, May 30, 2019, https://www.popsci.com/blue-light-blocking-glasses-science/
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