During the past few decades, humans have effectively hoisted technology to improve every segment of our daily life. From travel, work, and leisure time, technology is assisting us everywhere. This includes our extensive use of artificial light, which today emanates from a dizzying array of sources. Most jobs require us to be hooked on the computer for a good portion of our day. Our smartphones have become a fifth limb on our bodies.
In fact, according to some research, Americans are now spending 11 hours each day interacting with different light-emitting media17, which would roughly amount to two-thirds of our waking time. Some more striking facts reveal the following:
– 8 billion devices will be connected to the internet by 2020, which is roughly the same number of people living on this planet (even though only 40% of the world’s population make use of the internet)1;
– Over 570 new websites are launched every minute1;
– Also happening every minute: 24 hours of video is being uploaded to YouTube. By 2020 it is estimated that video will account for about 80% of all internet traffic1. We really are hooked on video!
The fraction of the data above speaks volumes about how much time we expose ourselves to light coming from electronic devices, which mainly emit blue light. But few of us understand the effects of persistent blue light exposure and how it can be hazardous to our own health. Too much blue light exposure will hurt our eyes, can disturb our sleeping pattern, and can even contribute to the development of different diseases such as diabetes, obesity, cancer, or heart disease9.
Research carried out at Oregon State University even suggests that extensive daily exposure to blue light may accelerate aging by effectively causing damage in retinal cells (what we use to see) and brain neurons (what we use to think), and impairing the locomotive system (what we use to move)16. This may happen even if you don’t absorb the blue light directly through your eyes, but simply from exposing your skin to it at home and at work where it’s emitted from various household fixtures and devices9.
Blue light is present in natural sunlight; it’s part of the visible light spectrum (ranging between approximately 380nm to 485nm)11. One of the key characteristics of blue light is that it’s energy efficient18, which is why it’s used as the primary source of artificial light in our indoor environments. Critically, it’s emitted from our smartphones, computers, and TVs.
In 2014, Japanese physician Shuji Nakamura and two of his close collaborators nabbed a Nobel Prize in Physics for inventing the blue Light Emitting Diode (LED), which represented a major breakthrough in lighting technology–much more energy-saving and efficient than any other lighting alternative. Only 5% is wasted as heat when LEDs is converted into light, and the rest is pure light energy18. Blue light has successfully begun to replace traditional incandescent lighting, and so is becoming a bigger part of our lives.
Since then, we have improved our LED technologies by removing the red and near-infrared (NIR wavelengths) from the great majority of our light sources, but we had not foreseen that there might be some perils at hand from this increase in exposure to blue light. Little did we know how this may affect our sleep, for instance.
Evolutionary speaking, we are accustomed to absorbing blue light from natural sunlight where it’s emitted alongside other wavelengths of light, such as red light. Naturally occurring blue light has a therapeutic effect on us. When we absorb blue light from artificial light sources, we react to it differently.
While blue light is great for our bodies during the day when we take it in from the sun, most problems occur at night, as we unknowingly sink in a blue-lighted world inside our very own homes.
When we expose ourselves to blue light during the dark hours of the day, we are basically telling our brains that the sun is still up, which is how we mess with our circadian rhythm16. Circadian rhythms are important as they determine the sleeping and feeding patterns of all animals, including humans6. In the brain, a small group of hypothalamic nerve cells (the suprachiasmatic nucleus (SCN)) function as a master circadian pacemaker controlling the timing of the sleep-wake cycle and coordinating this cycle with other brain and body systems to direct behavior appropriately15.
So, when you use your smartphone before falling asleep, you are basically telling your brain to stay awake5. You could instead cuddle your pillow, cat, dog, or partner–whoever/whatever is next to you.
Blue light affects melatonin, a hormone primarily released by the brain (pineal gland) and which actively regulates our brain’s sleep-wake cycle1. Blue light has been found to impair the body’s natural flow of melatonin. It negatively affects both our capability to sleep as well as the quality of sleep8,3, which is why you may end up waking up all grumpy and cranky in the morning after binging on funny cat videos5.
Blue light can also affect our mental health, and this particularly seems to resonate true for younger populations. Researchers have shown a 37% increase in reported mood disorder symptoms among young people over a nine-year period8,3. Early exposure to electronics has been named as one of the possible reasons behind the phenomena12. According to another recent study, children’s eyes absorb more blue light than adults from digital device screens, making children even more susceptible to blue light harms2.
Blue light can also induce photoreceptor (retina) damage, which is why it’s important to consider the spectral output of LED-based light sources to limit this threat associated with blue light exposure19. The retina is adapted to capturing light photons (the smallest unit of light) and transmitting this information to other parts of the nervous system7. But when the retina is faced with excess blue light, this may lead to retinal damage and stimulate genetic retinal diseases7.
More than that, excessive blue light coming in from devices contributes to premature aging of the eyes11. Combined with fatigue, dry eyes or even how we are positioned to the screen, blue light contributes to the development of so-called “digital eye strains,” the symptoms of which are having difficulty focusing or sore and irritated eyes11, 2.
In some cases, people with certain conditions experience worse symptoms from blue spectrum LEDs as replacements for older incandescent lamps. This greatly concerns light-sensitive individuals who struggle with skin conditions such as solar urticaria (skin hives) or chronic actinic dermatitis (photosensitive eczema)10. Both these conditions require avoidance of sun exposure as well as avoidance of exposure to blue light.
Lastly, as artificial blue light negatively affects the circadian cycle, it has been associated with a range of conditions: from immune system disorders to macular degeneration, cardiovascular diseases, diabetes, osteoporosis, and breast cancer to name some10.
While blue light can cut short some of your electricity bill, for the sake of your health, it’s best to expose yourself to blue light outside. Sunlight is the best source to get it2.
Getting a natural sun exposure nurtures the SCN (the biological rhythm pacemaker) as the blue light is combined with other lights from the spectrum, and subsequently:
– Helps to regulate your sleeping cycle when absorbed alongside red light2,15(and as your sleep improves you will generally feel more vital and energetic);
– Boosts alertness, helps memory and cognitive function and elevates mood2;
– Contributes to better hormone levels, body temperature, and digestion;
– Efficient exposure to natural blue light may also play an important factor in eye health and reduce the risks of conditions such as myopia (nearsightedness)2;
– And lastly, Light Therapy can help your body fight the effects of excess blue light14.
Apparently, too much exposure to blue light is no good, nor is too little of it. There are several steps that you can take to balance your exposure to blue light, however.
Tip 1: The first tip is obvious. Get more sunshine! While there is naturally more sunshine during summer, try to avoid staying inside during the winter when the sunlight is rarer.
Tip 2: Decrease your screen time. Limiting screen time may be the one most significant thing you can do to protect your health from unwanted consequences of excess blue light, especially at night12. So work and interact with electronics when the sun is up. There’s plenty to do afterward. Socialize and spend more time with friends and family. If you stay alone the night, get off the screen at least an hour before going to bed.
Tip 3: Adjust the screen brightness of your devices. Search for the “Dim” light setting on your phone. Do the same on your computer.
Tip 4: If your work consists of an overwhelming amount of screen time and/or you’re a gamer, consider buying a pair of blue light glasses. Their purpose is to block the blue light you expose your eyes to. You can also opt for light-blocking eyewear and software to limit your device blue light emission4.
Tip 5: Last but not least, improve the lighting installations in your home, especially if you use a lot of energy-efficient LED lights. Switch to light bulbs that are warmer in color (more red) and avoid installing too many that have the cold colors (such as blue).