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BLUE-LIGHT BLOCKING GLASSES

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Do you snuggle up with your smartphone or watch TV from the comfort of your bed? Blue-light emitting from digital devices may affect your sleep and cause sleep dysfunction, researchers have found.

The largest source of blue light is sunlight, but it's also found in most LED-based devices. Blue light boosts alertness and regulates our internal body clock or circadian rhythm, that tells our bodies when to sleep.

This artificial light activates photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGCs), which suppresses melatonin.

Lead researcher of the study recommends limiting screen time, applying screen filters, wearing computer glasses that block blue light or use anti-reflective lenses to offset the effects of artificial light at night-time.

"By using blue-light blocking glasses we are decreasing input to the photoreceptors, so we can improve sleep and still continue to use our devices," said Lisa Ostrin, Assistant Professor at the University of Houston.

The participants of the study, published in the journal 'Ophthalmic and Physiological Optics', wore short wavelength-blocking glasses three hours before bedtime for two weeks, while still performing their nightly digital routine.

The results showed about 58 percent increase in their night time melatonin levels, the chemical that signals your body that it's time to sleep.

Wearing activity and sleep monitors 24 hours a day, the study participants also reported sleeping better, falling asleep faster and even increased their sleep duration by 24 minutes a night, Ostrin mentioned.

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Blue-light blocking glasses may help you sleep better

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Do you snuggle up with your smartphone or watch TV from the comfort of your bed? Blue-light emitting from digital devices may affect your sleep and cause sleep dysfunction, researchers have found. The largest source of blue light is sunlight, but it's also found in most LED-based devices.

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HOW TO SLEEP BETTER - LIGHT

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Understanding "How do I Sleep Better" | Dr. Vyga Kaufmann | TEDxBoulder

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Have we all thought that we could sleep better? Can we solve sleep? Dr. Vyga Kaufmann discusses just what sleep disorders are and what tools you have to sleep better tonight. Hint: no square screens anywhere near your bed.

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Your bedroom should be free from any light.

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GIVE UP LIGHT/TECH FOR SLEEP

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Give it up for the down state -- sleep | Sara Mednick | TEDxUCRSalon

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Dr. Sara Mednick is Assistant Professor in the Department of Psychology at the University of California, Riverside. Her work on sleep research continues to shape the way we understand the importance of healthy sleep hygiene. In her talk, she argues for everyone to take a break.

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SMARTPHONE LIGHT AND SLEEP

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In today's digital age, many of us are guilty of being glued to our devices at all hours of the day, including when it's time to get some rest. Using your smartphone or tablet before bedtime seems harmless, but it might be affecting how well you sleep, according to new research.

The results of a small study, published in the journal Ophthalmic & Physiological Optics, adds to an extensive body of research that highlights the negative effects artificial light has on sleep quality. Participants who wore short wavelength-blocking glasses several hours before they went to bed had nearly a 58 percent increase in the amount of melatonin their body produced at night. Melatonin is a natural hormone, produced by a tiny gland in your brain, that lets your body know when it's time to sleep, according to the National Sleep Foundation.

In addition to the objective sleep measures, the researchers also collected subjective sleep quality data through the Pittsburgh Sleep Quality Index (PSQI). Results from the self-report questionnaire showed that study participants reported sleeping better, falling asleep faster, and sleeping longer each night.
Read: Fertility Problems: Why Artificial Light Harms Chance of Pregnancy For Middle-Aged Women
"The most important takeaway is that blue light at night time really does decrease sleep quality," Dr. Lisa Ostrin, an assistant professor at the University of Houston College of Optometry, who lead the study, said in a statement. "Sleep is very important for the regeneration of many functions in our body."

In the study, Ostrin and her colleagues monitored the activity and sleep patterns of 21 participants, ages 17-42 years old. Each individual was asked to put on short wavelength-blocking glasses three hours before they went to bed for two full weeks. During this time, they were assigned to engage in their usual nightly digital routine. The researchers collected data through several different methods: simulation to analyze pupil response; wearable actigraph devices to monitor activity, light exposure, and sleep; and saliva samples to assess melatonin levels.
Read: Sleep Disorder May Be Early Sign Of Parkinson's Disease And Other Neurological Conditions
Melatonin is suppressed when the body is exposed to artificial light, such as the blue light found in a majority of LED-based devices. This occurs because the artificial light activates photoreceptors, which prevent melatonin production. To combat the negative effect of blue light, Ostrin recommends using specific glasses that block the light.
See also: Tricking Your Mind Into Falling Asleep: Placebo Eases Insomnia Symptoms, Review Says Get Better Sleep: Infographic Shows Why You Can't Make Up For Hours Of Missed Sleep
"By using blue blocking glasses we are decreasing input to the photoreceptors, so we can improve sleep and still continue to use our devices," she said. "That's nice, because we can still be productive at night."

She also suggests using anti-reflective lenses, spending less time using screens, and applying screen filters to help block artificial light.

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How Your Smartphone May Affect Your Sleep

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In today's digital age, many of us are guilty of being glued to our devices at all hours of the day, including when it's time to get some rest. Using your smartphone or tablet before bedtime seems harmless, but it might be affecting how well you sleep, according to new research.

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LIGHT IMPACTS SLEEP

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Darkness Matters - How Light Affects Sleep

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Light has a profound effect on sleep. With awareness, attention, and some simple planning, you can create a bedroom that protects the quality of your sleep until you are ready to wake.

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BLUE LIGHT AND SLEEP

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In the modern age of technology it is not uncommon to come home after a long day at work or school and blow off steam by reading an e-book or watching television. Lately, however, scientists have been cautioning against using light-emitting devices before bed. Why? The light from our devices is "short-wavelength-enriched," meaning it has a higher concentration of blue light than natural light-and blue light affects levels of the sleep-inducing hormone melatonin more than any other wavelength.

Changes in sleep patterns can in turn shift the body's natural clock, known as its circadian rhythm. Recent studies have shown that shifts in this clock can have devastating health effects because it controls not only our wakefulness but also individual clocks that dictate function in the body's organs. In other words, stressors that affect our circadian clocks, such as blue-light exposure, can have much more serious consequences than originally thought.

To discuss the growing concern Scientific American MIND consulted with Thomas Jefferson University neuroscientist George Brainard, who was among the first researchers to investigate how different wavelengths of light affect the release of melatonin, and Harvard University neuroscientist Anne-Marie Chang, who recently discovered that the effects of light-emitting devices on circadian systems extend beyond evening and into the following morning.

[ An edited transcript of the conversation follows]

How did you become interested in the effects of light on sleep?
Brainard: I was interested in the effects of light on animals as a teenager. I never planned to be a scientist-I wanted to be a writer! So I learned more about the topic out of pure curiosity. When I began my career as a journalist, I interviewed researchers on the topic who encouraged me to pursue a career in science. So I returned to school to get my doctorate and studied the effects of different wavelengths and intensities of light on rodents. I have exclusively studied the effects of light on humans for the past 30 years.

Chang: As a graduate student, I researched circadian rhythm disorders resulting from different human sleep patterns, particularly those of early and late sleepers. I became interested in the effects of various aspects of light-such as time of day and duration of exposure-on circadian rhythm, sleep and performance.

How exactly does light affect our circadian rhythms? And how is melatonin involved?
Chang: We have known for quite awhile now that light is the most powerful cue for shifting the phase or resetting the time of the circadian clock. We also know that melatonin is present at low levels during the day, begins being released a few hours before bedtime and peaks in the middle of the night. Past studies have shown that light suppresses melatonin, such that light in the early evening causes a circadian delay, or resets the clock to a later schedule; and light in the early morning causes a circadian advancement, or resets the clock to an earlier schedule.

So how did scientists become interested in blue light in particular?
Brainard: In the 1990s my team performed more than 700 experiments over seven years to measure how different wavelengths of light regulate acute melatonin production. Unexpectedly, we found that humans display a peak sensitivity to light in the blue wavelength region of the spectrum.

Rods and cones [photoreceptors in the eye] could not account for this differential regulation of melatonin production, so we postulated another type of photoreceptor was responsible for mediating such physiological responses. These wavelength-sensitive photoreceptors were identified soon after and are known as melanopsin-containing ganglion cells.

What happens in the body when our eyes are exposed to blue light on electronic devices?
Chang: Recent studies have shown that short-wavelength [blue] light has a greater effect on phase shifting the circadian clock and on melatonin suppression. In 2014 my colleagues and I examined the effects of reading on a light-emitting device compared with reading a printed book. Participants who read on light-emitting devices took longer to fall asleep, had less REM sleep [the phase when we dream] and had higher alertness before bedtime [than those people who read printed books]. We also found that after an eight-hour sleep episode, those who read on the light-emitting device were sleepier and took longer to wake up. In the study all participants had to stop reading and turn off the lights at exactly 10 P.M., even if they did not feel sleepy. At home, I would expect people do not have the motivation to turn off their devices and go to bed, so they would stay up longer and experience even more circadian delay and shorter sleep times. The effects in the real world could actually be even greater.

What about extreme environments in which the body does not experience a normal daily cycle of sunlight and darkness?
Brainard: My research into the clinical applications of light got NASA interested in applying these findings to spaceflight scenarios. When an astronaut leaves Earth, his or her body is operating on a 24-hour light/dark cycle, but the space station orbits Earth every 90 minutes, and astronauts see the sun rise and set each time. This shift in the lighting environment, known as slam shifting, can have many health consequences and inspired my work with NASA on creating light-exposure schedules specifically for astronauts. [ Editors' Note: As a result of this work, NASA will begin implementing a new lighting system onboard the International Space Station next year, designed to improve astronauts' sleep and waking performance.]

Can the effects of light on melatonin ever benefit the body?
Brainard: My research in the 1980s showed that the effect of light on melatonin secretion has clinical benefits. Since then, light therapy has been shown to be effective in treating several other conditions, including depression, sleep disorders, eating disorders and age-related dementia.

Chang: Short-wavelength light can be applied in different circumstances where you actually want to shift the clock. For example, it could help in the mornings when we need to be at peak alertness or in cases of jet lag when we change time zones abruptly and our circadian clocks get thrown off. People with variable sleep patterns, such as shift workers, could also benefit from using a schedule of short-wavelength light exposure to help realign their circadian clocks.

Finally, the question everyone is wondering about: Do you have any suggestions as to what we can do to reduce our blue-light exposure before bed?
Chang: For those who just cannot turn off digital devices, here are a few suggestions: You can dim the brightness of your devices or you can make use of programs that filter out short-wavelength light in the evening. I've also heard of modern technologies that use different settings, such as reversing the print so the page is dark and the text is light, which, though untested, are probably beneficial if they reduce the amount of emitted light. But the best and least popular answer would be to simply avoid your devices before going to sleep!
READ SCIENTIFIC AMERICAN MIND'S SEPTEMBER/OCTOBER ISSUE TO LEARN HOW MODERN LIFESTYLES SCRAMBLE THE BODY'S RHYTHMS.

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Q&A: Why Is Blue Light before Bedtime Bad for Sleep?

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In the modern age of technology it is not uncommon to come home after a long day at work or school and blow off steam by reading an e-book or watching television. Lately, however, scientists have been cautioning against using light-emitting devices before bed. Why?

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Consider using blackout curtains, eye shades, ear plugs, "white noise" machines, humidifiers, fans and other devices.

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BLUE LIGHT AND SLEEP

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Exposure to blue light at night, emitted by electronics and energy-efficient lightbulbs, can be harmful to your health.

Until the advent of artificial lighting, the sun was the major source of lighting, and people spent their evenings in (relative) darkness. Now, in much of the world, evenings are illuminated, and we take our easy access to all those lumens pretty much for granted.

But we may be paying a price for basking in all that light. At night, light throws the body's biological clock-the circadian rhythm-out of whack. Sleep suffers. Worse, research shows that it may contribute to the causation of cancer, diabetes, heart disease, and obesity.

But 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. And the proliferation of electronics with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown.

Daily rhythms influenced by light

Everyone has slightly different circadian rhythms, but the average length is 24 and one-quarter hours. The circadian rhythm of people who stay up late is slightly longer, while the rhythms of earlier birds fall short of 24 hours. Dr. Charles Czeisler of Harvard Medical School showed, in 1981, that daylight keeps a person's internal clock aligned with the environment.

The health risks of nighttime light

Some studies suggest a link between exposure to light at night, such as working the night shift, to some types of cancer, diabetes, heart disease, and obesity. That's not proof that nighttime light exposure causes these conditions; nor is it clear why it could be bad for us. But we do know that exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms, and there's some experimental evidence (it's very preliminary) that lower melatonin levels might explain the association with cancer.

A Harvard study shed a little bit of light on the possible connection to diabetes and possibly obesity. The researchers put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.

Even dim light can interfere with a person's circadian rhythm and melatonin secretion. A mere eight lux-a level of brightness exceeded by most table lamps and about twice that of a night light-has an effect, notes Stephen Lockley, a Harvard sleep researcher. Light at night is part of the reason so many people don't get enough sleep, says Lockley, and researchers have linked short sleep to increased risk for depression, as well as diabetes and cardiovascular problems.

The power of the blues

While light of any kind can suppress the secretion of melatonin, blue light at night does so more powerfully. 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).

In another study of blue light, researchers at the University of Toronto compared the melatonin levels of people exposed to bright indoor light who were wearing blue-light-blocking goggles to people exposed to regular dim light without wearing goggles. The fact that the levels of the hormone were about the same in the two groups strengthens the hypothesis that blue light is a potent suppressor of melatonin. It also suggests that shift workers and night owls could perhaps protect themselves if they wore eyewear that blocks blue light. Inexpensive sunglasses with orange-tinted lenses block blue light, but they also block other colors, so they're not suitable for use indoors at night. Glasses that block out only blue light can cost up to $80.

Less-blue light

If blue light does have adverse health effects, then environmental concerns, and the quest for energy-efficient lighting, could be at odds with personal health. Those curlicue compact fluorescent lightbulbs and LED lights are much more energy-efficient than the old-fashioned incandescent lightbulbs we grew up with. But they also tend to produce more blue light.

The physics of fluorescent lights can't be changed, but coatings inside the bulbs can be so they produce a warmer, less blue light. LED lights are more efficient than fluorescent lights, but they also produce a fair amount of light in the blue spectrum. Richard Hansler, a light researcher at John Carroll University in Cleveland, notes that ordinary incandescent lights also produce some blue light, although less than most fluorescent lightbulbs.

What you can do

Use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin.

Avoid looking at bright screens beginning two to three hours before bed.

If you work 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.

Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.

image: © Innovatedcaptures | Dreamstime.com

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Blue light has a dark side - Harvard Health

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Until the advent of artificial lighting, the sun was the major source of lighting, and people spent their evenings in (relative) darkness. Now, in much of the world, evenings are illuminated, and we take our easy access to all those lumens pretty much for granted.

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BLUE LEDs IMPACT SLEEP

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Research has found that exposure to blue light suppresses the production of the sleep hormone melatonin more than any other type of light.

Credit: Ng Wei Keong | Shutterstock.com

Fluorescent bulbs and light-emitting diodes (LEDs) have taken over lighting because they are more energy efficient and can provide better lighting than incandescent bulbs. They are found in everything from task lighting to televisions to smartphones. But while these bulbs are helpful in many ways, they can also have a negative effect on sleep.

All artificial light, including LEDs, fluorescent bulbs and incandescent bulbs, can interrupt normal sleep patterns. The body's biological clock works in rhythms that are set by the amount of light and dark the body is exposed to. This is called the circadian rhythm. Circadian rhythms control the timing of many physiological processes. They determine sleeping and feeding patterns, as well as brain activity, hormone production and cell regeneration.

When the body is exposed to only to the natural light of the sun, the hypothalamus area of the brain sets its sleep patterns according to when it is light outside and to when it is dark. Light is detected by the retina, which sends signals to the hypothalamus. When it starts getting dark outside, the hypothalamus signals to the body to start creating sleep hormones, like melatonin, and to drop the human's body temperature to prepare for sleep, according to the National Sleep Foundation. In the morning, when light is sensed, the body is told to warm up and to produce hormones, like cortisol, that wake the body up.

When artificial light is added to a human's day, the body's natural rhythms become confused. The retina can now receive light no matter what time of day it is, so the body doesn't know when to get ready for sleep. A study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism found that, when compared with dim light, exposure to room light during the night suppressed melatonin by around 85 percent in trials.

Fluorescent and LEDs bulbs create a two-fold problem when it comes to sleep. First, they produce artificial light. Second, they produce blue light.

Blue light wavelengths produced by electronics and overhead lights boost attention, reaction times and mood, according to Harvard Medical School. This can be great for the daytime when the body needs to be alert, but at night it can become a problem.

Research has found that exposure to blue light suppresses the production of melatonin more than any other type of light. It is believed that the shorter wavelengths in blue light is what causes the body to produce less melatonin because the body is more sensitive to this type of light.

"In terms of light and our brains, there is a spectrum of wavelengths that impacts the human circadian system," said David Earnest, a professor and circadian rhythms expert at the Texas A&M Health Science Center College of Medicine. "Blue light is the most sensitive side of the spectrum."

A study by the University of Toronto found that those who wore glasses that blocked blue light wavelengths produced more melatonin than those who didn't during night shifts. Other studies have found that blue wavelengths suppress delta brainwaves, which induce sleep, and boost alpha wavelengths, which create alertness.

To get better sleep, it would be best to stop using artificial light altogether, but that isn't possible in modern times. There are some more reasonable solutions, though.

"To prevent sleeping problems, avoid any exposure to blue light 30 to 60 minutes prior to bed. That means, no TV, tablets, computers or smart phones," said Dr. Robert Oexman, director of the Sleep to Live Institute. "Ideally, you want your environment to be dimly lit so your body can start naturally producing melatonin."

Andrew Simon, a naturopathic physician at the Bastyr Center for Natural Health, also suggested changing all overhead lights to full spectrum if possible, and to use some of the new smart home tech solutions to have lights turn off gradually or at a certain time, to help encourage the body's natural sleep/wake cycle.

If these steps aren't possible, dimming devices and wearing blue light filtering glasses can help.

Additional resources

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Fluorescent bulbs and light-emitting diodes (LEDs) have taken over lighting because they are more energy efficient and can provide better lighting than incandescent bulbs. They are found in everything from task lighting to televisions to smartphones. But while these bulbs are helpful in many ways, they can also have a negative effect on sleep.

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Design your sleep environment to establish the conditions you need for sleep.

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TECHNOLOGY AND SLEEP

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Three ways gadgets are keeping you awake

Our cell phones, tablets, computers and other electronic gadgets have become such a huge part of our daily lives that it's often hard to put them down-even at bedtime. Keeping your phone on your nightstand may not seem like a big deal, but technology affects your sleep in more ways than you realize. Whether you're surfing the web, playing a video game, or using your phone as an alarm clock in the late evening, you're probably keeping yourself from a restful night. Learn the facts about digital devices, below, so you can nip your tech habits in the bud.
They Suppress Melatonin.
The blue light emitted by screens on cell phones, computers, tablets, and televisions restrain the production of melatonin, the hormone that controls your sleep/wake cycle or circadian rhythm. Reducing melatonin makes it harder to fall and stay asleep. Most Americans admit to using electronics a few nights a week within an hour before bedtime. But to make sure technology isn't harming your slumber, give yourself at least 30 minutes of gadget-free transition time before hitting the hay. Even better: Make your bedroom a technology-free zone-keep your electronics outside the room (that includes a TV!).
They Keep Your Brain Alert.
It may seem harmless to knock out a few emails before bed or unwind with a favorite movie, but by keeping your mind engaged, technology can trick your brain into thinking that it needs to stay awake. And if you're surfing the web, seeing something exciting on Facebook, or reading a negative email, those experiences can make it hard to relax and settle into slumber. After spending an entire day surrounded by technology, your mind needs time to unwind.
They Wake You Up.
Just because you're not using your cell phone before bed doesn't mean that it can't harm your sleep: Keeping a mobile within reach can still disturb slumber, thanks to the chimes of late night texts, emails, calls, or calendar reminders. About 72 percent of children ages six to 17 sleep with at least one electronic device in their bedroom, which leads to getting less sleep on school nights compared with other kids, according to their parents. The difference adds up to almost an hour per night, and the quality of snoozing is negatively affected too. To get a better night's slumber, parents can limit their kids' technology use in the bedroom, and mom and dad should be solid role models and set the tone by doing the same.

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How Technology Impacts Sleep Quality | Sleep.org

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Our cell phones, tablets, computers and other electronic gadgets have become such a huge part of our daily lives that it's often hard to put them down-even at bedtime. Keeping your phone on your nightstand may not seem like a big deal, but technology affects your sleep in more ways than you realize.

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BLOCKING BLUE LIGHT

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Sleep is highly underrated.

It is one of the "pillars" of optimal health ... just as important as diet and exercise.

Poor sleep is linked to heart disease, type 2 diabetes and depression. It is also one of the strongest risk factors for obesity ( 1, 2, 3, 4).

The problem is that humans are sleeping much less than they did in the past.

But that's not the end of it, unfortunately... the quality of our sleep has suffered as well.

It turns out that perhaps the single biggest contributor to our collective sleep problems, is the use of artificial lighting and electronics at night.

These devices emit light of a blue wavelength, which tricks our brains into thinking that it is daytime ( 5).

Numerous studies suggest that blue light in the evening disrupts the brain's natural sleep-wake cycles, which are crucial for optimal function of the body ( 6, 7).

Fortunately, this problem has a simple solution and there are a few actionable steps you can take to get rid of that blue light in the evening, potentially improving your health at the same time.

Let me explain how that works...

Blue Light is Crucial in The Daytime... But a Disaster at Night

Our bodies have an internal "clock" that is situated in the brain.

This clock regulates our circadian rhythm, the 24-hour biological cycle that influences many internal functions ( 8).

Most importantly, it determines when our bodies are primed to stay awake and be productive, and when we feel tired and want to go to sleep ( 9).

The circadian rhythm isn't 100% accurate. Sometimes it is a bit longer than 24 hours, sometimes a bit shorter.

For this reason, it needs signals from the external environment in order to adjust itself. The most important signals that adjust this internal clock are daylight and darkness.

This actually makes perfect sense... throughout evolution, brightness meant that it was daytime and that we should be awake and get stuff done, while darkness meant that it was time to sleep and recover.

But not all light is equal, it is primarily light of a blue wavelength (blue light) that stimulates sensors in the eye to send signals to the brain's internal clock.

Keep in mind that sunlight and white light contain a mixture of various wavelengths. There is a lot of blue light within ( 10).

Getting blue light (especially from the sun) in the daytime is very important. It helps us to stay alert, while improving performance and mood ( 11).

There has even been some success using blue light therapy devices to treat depression, and blue light bulbs in an office can reduce fatigue and improve the mood, performance and sleep of workers ( 12, 13, 14).

But even though blue light is incredibly beneficial during the day, it can be a complete disaster if we are exposed to it in the evening.

The problem is that modern light bulbs and electronic devices (especially computer monitors), also produce large amounts of blue light and "trick" our brains into thinking that it is daytime.

When it gets dark in the evening, a part of the brain called the pineal gland secretes the hormone melatonin, which signals to our bodies and brains that it is time to get tired and go to sleep.

Blue light, whether from the sun or a laptop, is very effective at inhibiting melatonin production ( 15, 16).

This means that our bodies don't get the proper signal that it's time to go to sleep, reducing both the quantity and quality of our sleep.

Studies have linked melatonin suppression in the evening to various health problems, including metabolic syndrome, obesity and cancer, as well as mental disorders like depression ( 17, 18, 19, 20).

Many have speculated that melatonin-disrupting blue light may be one of the key drivers behind obesity and many of the chronic diseases that are so common today.

However... indoor lighting and electronic devices are a major part of the modern lifestyle and they aren't going away anytime soon.

Fortunately, there is a simple way to block blue light from entering your eyes and disrupting the natural sleep-wake cycle.

Bottom Line: Blue light in the evening tricks the brain into thinking that it is daytime, which inhibits the production of melatonin and reduces both the quantity and quality of sleep.

Using Blue-Blocking Glasses at Night is a Simple Way to Solve This Problem

The easiest and most effective way to avoid blue light in the evening, is to use amber-colored glasses.

These glasses effectively block all blue light, so your brain doesn't get the signal that it is supposed to stay awake.

Studies show that when people use blue-blocking glasses, even in a lit room or using an electronic device, they produce just as much melatonin as if it were dark ( 21, 22).

In one study, people's melatonin levels in the evening were compared during three different lighting conditions ( 23):

1. Dim light.

2. Bright light.

3. Bright light with blue-blocking glasses.

The graph below shows what happened to a typical subject's melatonin levels...

As you can see, the bright light almost completely suppressed melatonin production, while the dim light did not.

But the people wearing the blue-blocking glasses produced the same amount of melatonin as those being exposed to the dim light. The glasses almost completely blocked the melatonin suppressing effect of the bright light.

Now to the fun part... not only have blue-blocking glasses been shown to increase melatonin, studies also suggest that they can cause major improvements in sleep and mental performance.

In one study, 20 individuals were randomized to use either blue blocking glasses, or glasses that didn't block blue light, for 3 hours before bedtime. The study went on for two weeks ( 24).

The subjects using the blue-blocking glasses had major improvements in both sleep quality and mood.

These glasses have also been shown to greatly improve sleep in shift workers, when they put them on before bedtime ( 25).

There was also a study in elderly cataract patients, showing that blue-blocking lenses improved sleep and significantly reduced daytime dysfunction ( 26).

Overall, it seems pretty clear that using blue-blocking glasses in the evening is effective. Not only does it improve sleep, but it also improves mood and cognitive function.

Of course, this hasn't been studied in a large, long-term study... but given the immense importance of sleep for health, it wouldn't surprise me if these glasses could also help prevent chronic disease and lead to a longer life.

Bottom Line: Studies show that blue-blocking glasses increase melatonin production in the evening, leading to major improvements in sleep and mood.

Other Ways to Block Blue Light

If you don't want to use these glasses every night, then there are a few other ways to reduce blue light exposure in the evening.

One popular way is to install a program called F.lux on your computer.

This program automatically adjusts the color and brightness of your screen based on your timezone. When it is dark outside, the program effectively blocks all blue light from your computer and gives the screen a faint orange color.

Although I'm not aware of any study on it, many people who use the computer a lot in the evening claim that this program helps them fall asleep.

There are a few other things you may want to consider:

Turn off all lights in your home 1-2 hours before bedtime.

Get a red or orange reading lamp, which doesn't emit blue light. Candlelight works well too.

Keep your bedroom completely dark (highly recommended), or use a sleep mask.

It is also important to expose yourself to plenty of blue light during the day. If you can, go outside during the day and get some natural sunlight.

If that is not an option, consider using a blue light therapy device in the daytime. It is like a strong lamp that simulates the sun and bathes your face and eyes in blue light.

What to Expect

I have a long history of sleeping problems. It usually takes me at least an hour to fall asleep and I tend to wake up frequently throughout the night and feel poorly rested in the morning.

However... about a week ago, I purchased blue-blocking glasses from UVEX that can help block blue light.

I've set a reminder on my phone to always put them on at 8:30 pm. If I'm not home at that time, then I just put them on as soon as I get home in the evening.

After having them on for about 1-2 hours, I start feeling very relaxed and naturally tired.

Since I started using them, I've been falling asleep much faster and waking up refreshed in the morning. My mood has improved significantly and I'm finding it a lot easier to think and write.

I've personally tried a lot of different things in order to sleep better... but using blue-blocking glasses is by far the most effective sleep "hack" I have tried.

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How Blocking Blue Light at Night Can Transform Your Sleep

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Sleep is highly underrated. It is one of the "pillars" of optimal health ... just as important as diet and exercise. Poor sleep is linked to heart disease, type 2 diabetes and depression. It is also one of the strongest risk factors for obesity ( 1, 2, 3, 4).

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BLUE LIGHT AND SLEEP

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About Blue Light And Its Effect On Sleep

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Learn how blue light from mobile devices affects our sleep!

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#175: SLEEP, LIGHT, AND YOUR BRAIN

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We've discussed sleep and its impact on cognitive function before. We've also talked about various ways to optimize your sleep.

One common recommendation when it comes to improving sleep is to avoid bright light, particularly blue light, at night. But you can actually use light to your advantage in sleeping better.

Dr. Scott Killgore, Associate Professor of Psychology at Harvard Medical School, and Timo Ahopelto, the Finnish serial investor behind the HumanCharger and the Ōura ring, join Jesse on this episode to discuss sleep and light therapy.

Sleep Deprivation is Bad, Very Bad

Do you really need to hear this again? Sleep deprivation sucks for your brain. It affects your mood, your morality, your cognition, and your likelihood of making risky decisions.

You'll also see a decline in emotional intelligence. There's a significant decline in your overall ability to use emotions during periods of sleep deprivation. You become more emotionally volatile, with a lower tolerance for frustration.

In more bad news, you don't actually recognize your deterioration. In multiple studies, participants' sense of sleepiness will plateau at a certain point of sleep deprivation, but their performance will continue to decline.

Sleep Deprivation Resistance

One area of our cognition that seems resistant to sleep deprivation is higher order cognition, including the ability to plan. It's fairly resistant to sleep loss and we don't see massive declines.

Interestingly, introverts are better able to resist sleep deprivation. According to Hans Eysenck's theory of personality, introverts have a higher base level of cortical arousal than extroverts, that's why they don't need additional outside stimulation.

Introverts are better able to sustain performance after one night of sleep deprivation. However, their advantage over extroverts fades after subsequent nights of lack of sleep.

Finally, while healthy normal individuals see an increase in depression and anxiety while suffering from sleep deprivation, clinically depressed individuals experience the opposite. They become less depressed when sleep deprived, although the research isn't clear as to why.

The Connection Between Light and Sleep

Our circadian rhythm aligns with environmental levels of light. Exposure to light suppresses melatonin production, which promotes sleep onset.

Exposure to light in the evening, especially blue light, emitted by electronics, disrupts this natural cycle. And don't think you can turn off your computer and try to fall asleep an hour later. The negative effects last for several hours.

So we know about the detrimental effects of light, but we can harness light in a positive way.

One way is by getting more exposure to natural light - blue light - in the early morning. Get outside, even if it's overcast. When you get early morning sunlight, you'll feel more alert during the day and sleep better at night.

Benefits of Bright Light

Exposure to bright light at the right time of day has a whole host of further benefits. During winter months, when there is less sunlight, many people experience lethargy or depression. Finns know this more than most.

Ahopelto and his team found a surprising solution, and it's as easy as sticking earbuds in your ears. The HumanCharger looks like an iPod with earbuds, but instead of playing music, it shines bright light into your ears.

Just 12 minutes of this bright light in your ears is enough to get rid of "winter flu" symptoms.

And this is just the start of the possibilities of light therapy.

Dr. Killgore is currently conducting research on using light therapy to treat brain injuries. The theory is that by getting better sleep, your brain will have a better chance at healing itself.

While the data is still preliminary, it is promising. After six weeks of light therapy, quality of sleep has improved, and there are structural changes in the brain that are hopefully associated with physical recovery.

April is Contest Month!

Want a chance to win a brand-new HumanCharger? Valkee has given us two HumanChargers for the Smart Drug Smarts audience, and we'll be randomly selecting winners from those who leave us a glowing iTunes review* during the month of April. To be eligible to win, just...

1. Leave us a review on iTunes, then

2. Drop us an email with a screen-grab of your review, along with your mailing address.

We'll announce our contest winners at the beginning of May.

Or, don't bother waiting around for us...

You can grab your own HumanCharger direct from Valkee here. [affiliate link]

* Get it? "Glowing"? 😉

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We've discussed sleep and its impact on cognitive function before. We've also talked about various ways to optimize your sleep. One common recommendation when it comes to improving sleep is to avoid bright light, particularly blue light, at night. But you can actually use light to your advantage in sleeping better.

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DARKNESS IS ESSENTIAL TO SLEEP.