You’re getting ready for bed and right before drifting off to sleep you reach for your phone for a final scroll. Somehow minutes turn into hours and you wonder where the time went – we get it. We do it too. 📱🙈
However, this might not be the healthiest way for us to end our days. Many eye doctors and sleep specialists are concerned about the effects our screen time could have on our vision and our health, and the main cause of that concern is blue light.
“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,” says Czeisler, PhD, MD, and director of sleep medicine at Harvard Medical School. “It is a growing public health concern.”
So, what is blue light you ask?
According to the Harvard Health Letter, “not all colors of light have the same effect. Blue wavelengths—which are beneficial during daylight hours because they boost attention, reaction times, and mood—seem to be the most disruptive at night.” 💡
Basically, during the day, the blue light in sunlight is the signal to our brains that we should be up and about. 🌞Absence of blue light signals that we should be resting. The problem is that most of us spend our day surrounded by artificial sources of blue light that confuse these signals, particularly LED and fluorescent lights and the screens of our electronic devices.
Specifically, blue light suppresses the release of melatonin in our brains, which leads to a lower quality of sleep, which in turn can contribute to a variety of negative health effects. As Richard Stevens, PhD, a University of Connecticut cancer epidemiologist and light-at-night researcher, puts it, we are “darkness deprived.”
The best-documented consequence, by far, of excess evening light exposure is short-term sleep disruption. In one study, people in a sleep lab who read from an e-reader at night saw their nighttime melatonin levels drop by 55% after 5 days, took longer to fall asleep, had less restorative rapid eye movement (REM) sleep, and felt more groggy the next day than those reading a paper book. 📚
Another study, looking at teenagers, suggests they may be even more sensitive to light at night. Just an hour of exposure from a glowing device, like a phone, suppressed melatonin by 23%; 2 hours decreased it by 38%. 😴
Research is young, but some studies suggest that chronic exposure to excess light at night may also fuel cancer, in part by lowering the levels of melatonin -- a known anti-cancer agent -- circulating in the blood. Female night shift workers have a 50% to 70% greater chance of developing breast cancer during their lifetime, says David Blask, MD, associate director of the Tulane University Center for Circadian Biology.
So, what exactly should our relationship with blue light be?
Maximize bright light during the day
Mariana Figueiro, PhD, light and health program director at the Lighting Research Center in Troy, NY, stresses that in addition to minimizing bright blue-hued light -- especially from gadgets held close to the eyes -- at night, we should try to maximize the amount of bright light we get during the day. 🌻
“It not only makes you more awake and alert by day; research suggests it may also make you less sensitive to the negative health consequences of light at night,” she says.
So consider stepping into the sunshine for a quick walk in the morning. In your office, put your desk near a window. Invest in a bright light -- one that delivers 1,000 lux (a measure of light intensity) or more of blue-hued light at eye level -- to put on your desk at work. Studies show that most office environments are too dim to stimulate the positive, alerting effects of light by day.
One 2014 study by Northwestern University researchers even found that people who got most of their bright light exposure before noon were about 1.4 pounds leaner on average than those exposed to most bright light in the evening.
Power Down Devices the Hours Before Bed
Stevens says that beyond the 7 to 8 hours of sleep you try to get each night, you should make an effort to get 3 more hours of relative darkness. This means we should avoid looking at screens in the last hour or two before bed. If that sounds difficult, there are other options, all of which can also help with minimizing the effects of blue light on our vision.
You don't need to live by candlelight after dinner, but it’s a good idea to dim the lights and steer clear of bright blue screens. 🕯 Consider using dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin. If possible, invest in blackout shades if streetlights shine into your window, and look for an eye mask for when it’s time to go to sleep.
If all else fails, make your devices warmer
If you’re working a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses or installing an app that filters the blue/green wavelength at night. 🧐💕If you are using your phone constantly — especially if you use it primarily for texting, e-mailing and web browsing — a convenient way to reduce your blue light exposure is to use a blue light filter. Digital electronic devices emit blue light that can cause eye strain and may lead to eye problems over time.
These filters are available for smartphones, tablets, and computer screens and prevent significant amounts of blue light emitted from these devices from reaching your eyes without affecting the visibility of the display. Some are made with thin tempered glass that also protects your device's screen from scratches. Examples of blue light filters for digital devices include: Eyesafe (Health-E), iLLumiShield, and Cyxus blue light filter glasses. Whatever works for you, we hope these tips on blue light help you to wake up ready and refreshed come the morning! ☀️