Studies urge reduction or protection against bright-light-at-night exposure

by Ginger Sladky (23 Jan 2015)

The latest research performed by Brigham and Women’s Hospital (BWH) supports earlier findings that use of a light-emitting electronic device adversely impacts your health.  Participants reading on iPads [but also “eReaders, laptops, cell phones, LED monitors, and other electronic devices, all emitting blue light] took longer to fall asleep than participants reading printed books, were less sleepy in the evening, and spent less time in REM sleep.  The [electronic device] readers had reduced secretion of melatonin, a hormone which normally rises in the evening and plays a role in inducing sleepiness.  Additionally, [electronic device] readers had a delayed circadian rhythm, indicated by melatonin levels, of more than an hour.  Participants who read from the [electronic device] were less sleepy before bedtime, but sleepier and less alert the following morning, even after eight hours of sleep.


“In the past 50 years, there has been a decline in average sleep duration and quality,” stated Charles Czeisler, PhD, MD, FRCP, chief, BWH Division of Sleep and Circadian Disorders.   “Since more people are choosing electronic devices for reading, communication and entertainment, particularly children and adolescents who already experience significant sleep loss, epidemiological research evaluating the long-term consequences of these devices on health and safety is urgently needed.”   


It is well established that short-wavelength or “blue” light is the most melatonin-suppressive; this is the type of light typically emitted by devices such as televisions, computer screens, and cellphones. http://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side


Why do we care about our melatonin being suppressed?  Melatonin suppression caused by exposure to light-at-night and shift work has been definitively linked with

Obesity and metabolic syndrome: http://informahealthcare.com/doi/abs/10.3109/07853890.2011.586365

Cardiovascular disease: http://onlinelibrary.wiley.com/doi/10.1111/j.1600-079X.2010.00773.x/full

Depression: http://www.ncbi.nlm.nih.gov/pubmed/21476953

and Cancer (specifically colorectal, breast, and prostate): http://www.ncbi.nlm.nih.gov/pubmed/16596308  


What can we do?

“There are a few possible solutions for reducing your exposure to blue light at night”, claims Chris Kresser: 

“One that is commonly used in the ancestral health community is a program called f.lux, a program that makes the color of your computer’s display adapt to the time of day, warm at night and like sunlight during the day. This program can be installed on computers, iPads, and iPhones, and may have a significant effect on your melatonin secretion when using these devices at night. 

A better option, in my opinion, is to use amber-lensed goggles once the sun has gone down. These blue-blocking lenses are highly effective in reducing the effects of blue light exposure, and in most cases completely eliminate the short-wavelength radiation necessary for nocturnal melatonin suppression. (22, 23, 24) These goggles have been shown to improve sleep quality as well as mood, simply by blocking blue light and simulating physiologic darkness.

The main reason I recommend using these goggles is because normal room light alone is enough to suppress melatonin at night, and unless you’re shutting off all the lights in your house when the sun sets, you’re still at risk for disrupting your melatonin-driven circadian rhythms. (25) While f.lux is a useful tool for your backlit devices, it’s nearly impossible to address all sources of melatonin-suppressing light in today’s world of modern technology and late-night work and entertainment habits. Amber-colored goggles are one of the only tools available to completely eliminate all blue light exposure at night, without ‘going off the grid’ and powering down your entire house after 7 PM.” 

The two amber-colored goggles Chris recommends, which have received rave reviews from his patients, are the Uvex and Solar Shield brands.

Optimal of all tips to avoid harmful light exposure after dark:

  • Don’t use a computer for 2 hours before going to bed. No staying up late on Facebook/Instagram & Twitter! 
  • Use blackout shades to make your bedroom pitch black.
  • Cover your digital alarm clock or get an analog clock.
  • Turn off all digital devices that glow or give off any type of light.
  • If you can’t do these things for some reason, use a sleep mask.

See Chris Kresser’s site for links to additional supporting resources: http://chriskresser.com/how-artificial-light-is-wrecking-your-sleep-and-what-to-do-about-it

Check out our other Articles on Nutrition found Here!


+49 (0)911 321 67750 info@rcfn-training.com