Red Light, Blue Light, and Blood Sugar

Blue light from screens and devices can raise blood sugar and cortisol, while red-light therapy can lower them. Read on to find out why and what you can do.

Effects of Blue Light on Blood Sugar

Sunlight contains the most amount of blue light early in the morning, and the reception of it by the pineal gland in the brain tells the body to wake up and start producing cortisol. In a person whose circadian rhythm is in sync with natural rhythms, cortisol is highest in the morning and then slowly tapers off throughout the day, unless there is unregulated stress, free-floating anxiety or chronic inflammation that cause it to remain high. If cortisol is higher than it should be later in the day or in the evening, it will likely be difficult for such a person to fall asleep or to sleep well.

High cortisol levels can raise blood sugar, and blue light from screens and devices has been documented to raise blood sugar (see Sources & References, below). In the U.S. where 93% of the population is metabolically unhealthy, blue light from screens, LED and fluorescent lights may be contributing to the problem, especially with nighttime exposure.

Effects of Red Light on Blood Sugar

To counteract the effects of artificial blue light, red-light therapy has been shown to lower blood sugar (see Sources & References, below). In this particular study, red light of 670nm (nanometers) was shone on a subject’s back for just 15 minutes, and this was enough to lower test subjects’ average blood sugar by 28%. Researchers theorized that this particular wavelength stimulated energy production within mitochondria, which lead to increased consumption of glucose. This non-invasive therapy may have the potential to impact blood-sugar and insulin control in a non-pharmacological manner.

Putting It All Together

Research continues to bear out the fact that following natural circadian rhythms is best for human health. Most people don’t want to live off the grid or become a Luddite, so here are some practical ways for you and your family to peacefully coexist with technological innovations that may be harming health and raising blood sugar:

• Get as much bright morning light in the early morning as possible. This helps to reset one’s circadian rhythm and is also great advice for jet lag. Bonus points for putting bare feet onto wet grass or sand.
• Get as much natural light as possible throughout the day without getting sunburned. It’s not enough to sit by a window; the window must be open to let in natural light (plus, you’ll get fresh air).
• Avoid wearing sunglasses or blue-blocking glasses in the day, unless you’re looking at a computer, smartphone or other screen. The wavelengths of natural, full-spectrum sunlight signal circadian-based reactions such as hormone production. Blocking the sun’s rays can potentially impact the body’s systems.
• Use blue-light blocking apps like Iris or computers like Daylight Computers. These can automatically adjust the blue- and red-light dimensions of your screen throughout the day. (You can find out more about Daylight here: https://buy.daylightcomputer.com/HOPE, and use the code HOPE to get a $50 discount. Your purchase also benefits Documenting Hope.)
• Use blue-light blocking glasses after dark. These generally have red-tinted lenses. 
• Turn off overhead lights after dark. Use low-wattage bulbs for sidelamps. If you’re really brave, replace bulbs with red bulbs or use candles.
• If you have an iPhone, do a custom keybind to make your screen appear amber using Daniel White’s How to Hack Your Smartphone, PC & Laptop for Better Sleep. You can learn more tips in Daniel’s Top Tips for Better Sleep and Circadian Health webinar with us. (Personal note: I did this for my own iPhone and no longer have dry eyes.)
• Get a red-light therapy setup for home use. Peter Sullivan spoke about low-/no-EMF versions of these in his The Role of EMFs in Excitotoxicity, Autism and Seizures webinar with us. Scroll down on the page to the section on Resources Mentioned in This Webinar.
• For more tips on regulating blood sugar in general, view Dani Hamilton’s Blood Sugar Hacks webinar with us, read our Optimizing Blood Sugar article and read our review of The Glucose Goddess’ Glucose Revolution book.

About Maria Rickert Hong CHHC

Prior to working on Wall Street, she was a marketing specialist for Halliburton in New Orleans, where she also received her MBA in Finance & Strategy from Tulane University.

She is the author of the bestselling book Almost Autism: Recovering Children from Sensory Processing Disorder and the co-author of Brain Under Attack: A Resource for Parents and Caregivers of Children with PANS, PANDAS, and Autoimmune Encephalitis. She is a co-author of Reversal of Autism Symptoms among Dizygotic Twins through a Personalized Lifestyle and Environmental Modification Approach: A Case Report and Review of the Literature, J. Pers. Med. 2024, 14(6), 641.

Maria is also a Certified Holistic Health Counselor. Her work can be found on DocumentingHope.com, Healing.DocumentingHope.com, Conference.DocumentingHope.com and MariaRickertHong.com

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