If you feel as though you haven’t had a good night’s sleep in years, it’s quite possible that you haven’t. Certainly, the last 20 years of technology have been eating away at your quality and quantity of rest. One of the main culprits is the ongoing overuse of blue wavelengths of light. The visible spectrum of light goes from long wavelength, low frequency red, through the medium frequencies and colors, to short wavelength, high frequency blue. Short wavelength enriched blue light, which can be beneficial during the day because of its ability to boost reaction times, mood, and attention, can be detrimental at night for the same reasons.
If you’re spending a great deal of your evening hours in front of your television, your tablet, your computer and your phone screen, it’s a perfect recipe for wrecking your circadian rhythms. These rhythms are your natural body clock and the average cycle length is 24 and one-quarter hours—although some cycles are a bit shorter or longer. In 1981, Dr. Charles Czeisler of Harvard
Medical School showed normal daylight keeps a person’s internal clock aligned with the environment. When you use blue light emitting devices at night, you’re sabotaging yourself.
There is a physiological reason for human sensitivity to blue light. In an interview with Scientific American, Thomas Jefferson University neuroscientist George Brainard, explained there are special “wavelength-sensitive photoreceptors” in the eye “known as melanopsin-containing ganglion cells.” These are different from the regular rods and cones present in the eye.
Blue light suppresses the production of melatonin, a sleep-inducing hormone, in the body. There are other wavelengths that can suppress melatonin production, but none as destructive as blue light. According to Harvard Health Publications, “Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).”
The really bad news is what all this blue light is doing to teenagers in particular. Mariana Figueiro, of the Rensselaer Polytechnic Institute compared melatonin levels of adults and teenagers looking at computer screens, and found that when exposed to only one-tenth as much light as adults, the teens suppressed more melatonin than adults.
With all this blue light pollution, settling down to read a good book at night can sound like a great alternative. But that actually depends on what sort of bulb you’re using in your lamp. If it’s one of the newer compact fluorescent lightbulbs, or even LED lights, you guessed it—blue light emitting offenders. Richard Hansler, from John Carroll University in Cleveland, found “ordinary incandescent lights also produce some blue light, although less than most fluorescent lightbulbs.” Fortunately, there are now available special light bulbs that have red-tinted coatings on them to diminish the amount of blue light emitted, and instead emit a warmer, longer spectrum of light waves.
Since it is now known to be such a problem, manufactures are making more devices that can be dimmed at night to reduce the blue, short wavelengths. There are also certain apps that can filter blue and green wavelengths in the evening. If you must use a nightlight or a glowing alarm clock, opt for red bulbs, and red readouts. The red spectrum of light has the least influence on melatonin production. You can also buy glasses (prescription or non-prescription) that help block blue light.
The best advice of all—stop using your electronic devices before bedtime. Dr. Victoria Revell, a senior project manager at the Surrey Clinical Research Centre recommends shutting them off 2 hours ahead of your scheduled time to hit the hay to allow your body time to produce sufficient melatonin. Then you can sleep like you remember doing before all these devices came along to “make your life better”.