You may be reading this article in a dark room at 1 in the morning, or you may be reading this article at noon in the office—but either way, you could be disrupting your melatonin production.
Melatonin is produced in the brain (notably the pineal gland), the central nervous system, and in some neurons and meninges of the brain. It passes easily through the blood-brain-barrier and accumulates in the central nervous system. It is now also thought of as a naturally occurring free racial scavenger and is neuroprotective. Melatonin and its metabolites are also found in mitochondria and most free radical scavenging occurs at the mitochondrial level.
Blue light is short-wavelength light that is emitted from artificial sources of light. This includes all indoor lighting (like fluorescent lighting, LED light bulbs, compact fluorescent light bulbs, LED t.v., computer monitors, tablet screens, and smart phones).
Natural sunlight contains the largest amount of blue light and is made up of the whole rainbow of colors in light. All of the colors together form white light. The rays of light all have varying wavelengths, with red being the longest wavelength and least amount of energy, and blue being the shortest wavelength and the most energy of all the wavelengths.
The blue light wavelengths flicker because they are shorter and flickering causes glare, resulting in reduced visual contrast and can alter our vision’s normal sharpness and clarity. Prolonged exposure to the constant flickering causes eyestrain, physical and mental fatigue, and headaches. It is estimated that spending only 2 consecutive hours on a computer or phone causes fatigue and eyestrain.
The concern over blue light is because we are spending so much of our time in front of screens, and our eyes are much closer to the screen. We are experiencing disturbances in our sleep-wake patterns because unlike the sun which is only present for part of the day, we are saturated in our current world with sources of blue light long after the sun is down. Blue light exposure decreases melatonin production.
Blue light may also be harmful to the retina because it is absorbed by the retinal pigment epithelium and some photoreceptors found in the retina. This causes local oxidative and thermal stress. Children are especially susceptible to blue light because their growing lens absorbs much less of the short-wavelength light and more blue light reaches their retina. The blue light cannot damage the retina directly but can stimulate the photoreceptors in the retina that regulate our sleep-wake cycle, or circadian rhythm.
An estimated 75% of the world’s population is exposed to artificial light at night. Low levels of artificial light before bedtime from screens can reduce the secretion of melatonin, increase the time it takes to fall asleep, reduce overall sleepiness, and reduce alertness the next morning.
Most electronics have a blue-light filter which you can switch on, but it won’t protect you from flipping the bathroom or kitchen light on during the night, or from the overhead lights at work. A popular solution is blue light-blocking glasses. These are glasses that are amber-tinted and protect your eyes from blue light rays. You can wear them while you are at the office, or right before you start winding down and get ready for bed. There are many popular styles to choose from, but my favorite is the Spectra 479 Bio-Rhythm Safe glasses.