A lot of studies have explored the potential negative effects of light pollution and overexposure to light. Some studies suggest excess exposure is related to insomnia (this might come as a shock…not) and diseases like Alzheimer’s or Breast Cancer. With regard to light wavelengths, the blue wavelength is one of particular interest, especially for those of us who use mobile electronics on a daily basis.
Melatonin & Blue Light
The New York Times published an article that quotes researchers who discuss some of the effects blue light has on our eyes and the chemical imbalance of melatonin. Melatonin is a hormone that responds directly to any kind of light. As night approaches and the amount of light decreases, the body releases melatonin, which “promotes sleep and alerts a variety of biological processes to the approximate hour of the day.” However, when light strikes the retina, or back of the eye, melatonin is suppressed.
…there lies the rub. In this modern world, our eyes are flooded with light well after dusk, contrary to our evolutionary programming. Scientists are just beginning to understand the potential health consequences. The disruption of circadian cycles may not just be shortchanging our sleep, they have found, but also contributing to a host of diseases.
Scientists like George Brainard, a neurologist at Thomas Jefferson University in Philadelphia, have observed that blue light is especially effective at suppressing melatonin. Why is this relevant? Many backlit electronic screens implement LED technology that uses blue wavelength emitting diodes.
A group of researchers at the University of Basel in Switzerland conducted a study using 13 men that were asked to sit in front of different types of computer screens before retiring to bed. During one week, they spent five hours in front a fluorescent, red-based screen that emitted little blue light. During another week, they spent five hours in front of a LED, blue-based screen that emitted twice as much blue light. Notice the first screen emitted barely any blue, so twice as much blue light is significantly more, but it doesn’t mean the screen was screaming blue. This is significant to me because it seems to indicate that the study was more realistic and not taken out of context from the kinds screens people actually look at. So what were the results?
Melatonin levels in volunteers watching the LED screens took longer to rise at night, compared with when the participants were watching the fluorescent screens, and the deficit persisted throughout the evening.
And this is the most intriguing part:
The subjects also scored higher on tests of memory and cognition after exposure to blue light, Dr. Cajochen and his team reported in the May issue of The Journal of Applied Physiology. While men were able to recall pairs of words flashed across the fluorescent screen about half the time, some scores rose to almost 70 percent when they stared at the LED monitors.
My first impression after reading that was that I’ll continue to study for tests using my computer. Maybe that explains higher tests scores when I do use my computer? I haven’t looked into it but it’s an interesting thought.
Again, why is this relevant? Because we are readily replacing old red light technology like incandescent bulbs with new energy-efficient blue light technology like LEDs. Most of our new electronic screens use LED technology (TVs, laptops, flat screen monitors, mobile phones, etc.).
Research isn’t absolutely conclusive since this is a relatively immature field of study, but the findings are starting to lead scientists to more concrete conclusions. Health agencies are starting to make statements. The World Health Organization concluded that irregularities in biological clock patterns “can alter sleep-activity patterns, suppress melatonin production and disregulate genes involved in tumor development.” The Journal of the American Medical Directors Association made conclusions regarding the boost in cognitive processes made by subjects exposed to blue light as opposed to red light.
If you’re a little paranoid about your health, or maybe you want to ensure you’re sleeping your best, there are some technological solutions. f.lux (Mac, iPhone/iPad, Windows & Linux) is a free program that automatically adjusts the amount of blue light emitted by your screen depending on the time of day. So in the evening the screen changes to redder tones. During morning hours, screen color is designed to emulate natural sunlight. Don’t worry, your whole screen won’t turn red; you’ll just notice a it feels a bit warmer with regard to color temperature. You can also customize it for the best experience by adjusting how fast it transitions, how much the color changes and what kind of lighting you are surrounded with.
I suggest you give f.lux a try as today’s mini-app of the day. I’ve found it rests my eyes a bit more in the evening if nothing else.
Another Mac only alternative is a prefpane app called Shades.
If you’re interested in learning a bit more you can check out the articles listed on Stereopsis’s research link (the group that developed f.lux) or read some of the studies listed below.
- The impact of light from computer monitors on melatonin levels in college students
- Non-Visual Effects of Light on Melatonin, Alertness and Cognitive Performance: Can Blue-Enriched Light Keep Us Alert?
- Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness…
- High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light
- Melatonin rhythmicity: effect of age and Alzheimer’s disease
- Effect of Light Wavelength on Suppression and Phase Delay of the Melatonin Rhythm