Blue Light Sleep & Melatonin Study

How Blue Light Affects Sleep & Melatonin Levels A Secondary Research StudyBlue Lights Affects On Sleep & Melatonin Levels

A Secondary Research Study

This blue light sleep study discusses how blue light affects sleep, what computers / phones or other devices emit blue light, and finally some sleep aids that may be used to therapeutically filter, block, or otherwise mitigate blue light.

Disclaimer: this study is not intended as medical advice or therapeutic suggestion. Consult your doctor prior to making any choices that may affect your sleep.


According to the 2016 Digital Eyestrain Report by The Vision Council, 90% of Americans use digital devices for more than 2  hours every day, and 60% use digital devices more than five hours per day.  (*Consider that most workers are looking constantly at computers for 8 hours per day). 65% of Americans report symptoms (headache, blurred vision, dry eyes, back pain) of digital eye strain. “This constant exposure to technology is a shock to our eyes. For centuries, we have evolved our sight by viewing a wide variety of objects outside from varying distances.”

This Scientific American report  discusses why blue light in particular is bad for our sleep. “The light from our devices is “short-wavelength-enriched,” meaning it has a higher concentration of blue light than natural light—and blue light affects levels of the sleep-inducing hormone melatonin more than any other wavelength. Changes in sleep patterns can in turn shift the body’s natural clock, known as its circadian rhythm.”

So, when we ask the question, “does blue light affect your sleep”, the answer from reports like this is a resounding, YES. And, how, is simple, blue light reduces melatonin levels which signals to our bodies that it is time to sleep.

Expert Sleep Researcher Opinion

Noted in this article, back in 1981, Dr. Charles Czeisler demonstrated how daylight “keeps a person’s internal clock aligned with the environment”. In this 2017 webMD article, Dr. Charles Czeisler, who leads sleep medicine at Harvard Medical School and Brigham and Women’s Hospital’s Division of Sleep and Circadian Disorders in Boston, noted that “The more research we do, the more evidence we have that excess artificial light at night can have a profound, deleterious effect on many aspects of human health.It is a growing public health concern.” Dr. Czeisler is listed as a Principal Investigator for Research Funding of “Mechanism Underlying the Effects of Blue Light in Humans” study (National Institute of Complementary and Alternative Medicine).

Devices That Emit Blue Light

Devices that emit blue light include computer screens, cell / smart phone screens, LED Lights, including street lights (which have become a major issue of contention with cities installing street lights that emit blue light).  Further reading: Some Cities Are Taking Another Look at LED Lights After AMA Warning 

Reduce Effects of Blue Light

Harvard Report, Blue Light Has a Dark Side, recommends that to help reduce the effects of blue light on sleep,

  • Use red light as night lights because it affects melatonin the least.
  • Avoid digital screens up to 3 hours before bed time.
  • If working a night shift, think about using blue blocking or filtering glasses
  • Use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin.
  • Avoid looking at bright screens beginning two to three hours before bed.
  • If you work a night shift or use a lot of electronic devices at night, consider wearing blue blocker glasses. In a study titled, Blue blocker glasses impede the capacity of bright light to suppress melatonin production, published at the results seemed to confirm the hypothesis: “Blue blockers represent an elegant means to prevent the light-induced melatonin suppression. Further studies are needed to show that these glasses, which are suitable for driving, could facilitate adaptation to night work.”
  • Install a blue light blocking app that filters the blue/green wavelength: Here are a couple of popular choices: “The Twilight app makes your device screen adapt to the time of the day. It filters the flux of blue light emitted by your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The filter intensity is smoothly adjusted to the sun cycle based on your local sunset and sunrise times.” Blue light filter “is used to reduce blue light by adjusting the screen to natural color. Shifting your screen to night mode can relieve your eyes strain, and your eyes will feel at ease during night reading. Also blue light filter will protect your eyes and help you sleep easily.”
  • Get plenty of bright light during daytime, which helps one sleep at night.

When Blue Light Is Healthy, And Not Bad

It is worth noting that blue light is not always bad. Being exposed to blue light, which is produced naturally by the sun, increases activity levels and corresponding bodily processes (neurological & otherwise) required for the normal daytime operations historically carried out by humans over thousands of years.

Copyrights: Permission granted to use the information herein provided it is referenced appropriately.

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