An estimated 70 million Americans receive less than six hours of sleep per night[*][*]. Chronic sleep deprivation is a modern epidemic. Because of the introduction of energy-efficient lighting and digital devices, exposure to sleep-disrupting artificial light is increasing annually.
Insufficient or poor-quality sleep leads to inflammation in your body and disrupts your mood, performance, and focus. Even one night of sleep deprivation causes irritability, daytime sleepiness, and an inability to concentrate.
Sustained poor-quality sleep is associated with premature death and aging, as well as an increased risk of chronic diseases like heart disease, high blood pressure, diabetes, obesity, and cancer.
In this article, you’ll learn about circadian rhythms, why artificial light is to blame for many modern health issues, and how to improve your health and wellness using blue-blocking glasses.
What Are Circadian Rhythms?
Your body’s circadian rhythms are natural, twenty-four-hour rhythms that are mainly determined by the presence or absence of light in your environment. Circadian rhythms control what time you wake up, when you get hungry, what time you feel sleepy and go to bed, and when your body produces hormones.
In humans and other mammals, the suprachiasmatic nucleus (SCN), located in your hypothalamus, functions as the primary circadian clock. The SCN gets information from specialized light-sensitive cells in your eyes called retinal ganglion cells, which keep your body attuned to the light frequencies and day length in your local environment.
Your SCN communicates with your pineal gland to coordinate the release of melatonin, also called the sleep hormone, which allows your body to rest and repair itself at night. Cortisol, a steroid hormone that helps you wake up in the morning, also influences your sleep-wake cycles based on light in your environment[*][*].
Other organs in your body, including your digestive system, contain “clock” genes that oscillate (respond) to signals from the SCN as well as behavior patterns like activity and meal timing.
According to researchers, nearly half of all genes in mammals oscillate with circadian rhythm pathways[*]. A majority of best-selling pharmaceutical drugs in the United States target the products of circadian genes[*].
How Artificial Light Wrecks Your Sleep
Since the beginning of life on earth, humans and their ancestors evolved under predictable conditions of twenty-four-hour days, with transitions from light to dark marking daytime and nighttime. But over the past 130 years, electric lighting has transformed the global environment[*].
Even after the introduction of energy-efficient lighting, which emits more high-energy short-wavelength blue and green light, light pollution continues to increase annually[*].
Common behaviors like watching television at night, checking your phone in the dark, and turning on the lights after bedtime can disrupt your circadian rhythms and sleep-wake cycles by “tricking” your body into believing it’s daytime[*].
The industrialization of society has led to an increase in people suffering from sleep disorders because of artificial light at night[*]. These disorders, which result in insomnia and daytime sleepiness, occur when your circadian clock is out of tune with the natural twenty-four-hour day.
As a result of constant exposure to artificial blue light, most people are permanently “socially jet-lagged” in their daily lives–neither sleeping well nor feeling fully alert during the day[*].
#1: Decreased Sleep Quantity
When blue light shines into your eyes at night, it alters your sleep schedule. Viewing blue light three hours before bed can instantly set your sleep schedule back a full two hours[*].
Even a single night of blue light exposure before bed can cause sleep deprivation[*]. If you continue to use digital devices or other blue light sources before bed, your sleep schedule can be delayed further, even if you try to adjust your bedtime[*].
Multiple studies of humans and animals show that sleep deprivation for even one night can increase the formation of beta-amyloid plaque associated with Alzheimer’s disease, and chronic sleep deprivation causes further build-up[*][*][*].
A study of over 4000 adolescents between the ages of 11-17 found that sleep deprivation is associated with major depression[*]. And a separate review of 34 different studies concluded that sleep deprivation leads to heightened anxiety levels[*]
#2: Reduced Sleep Quality
Sleep quality is a measure of the sleep cycles your body goes through at night. These cycles include light sleep, deep sleep, and REM sleep (when dreaming occurs). While deep sleep is crucial for your body to repair itself, REM sleep is the time when your brain consolidates memories and prepares for the coming day.
Even if you sleep a full eight hours, poor sleep quality from artificial light is detrimental to your health and performance. The International Agency for Research on Cancer has classified this form of sleep disruption as a “probable carcinogen to humans”[*].
In athletes, poor sleep leads to unwanted weight gain, reduces speed, endurance, attention, and memory, and increases the risk of illness and injury[*]. A study of 28 healthy males found that reduced sleep quality reduced maximum heart rate, VO2max, and power output during physical activity regardless of physical fitness[*].
#3: Long-Term Effects of Disrupted Sleep
According to a 2012 estimate, at least 70 million adults in the United States regularly get less than six hours of sleep per night, which is less than previous decades[*]. Inadequate sleep is comparable to a sedentary lifestyle when it comes to causing insulin resistance and type 2 diabetes[*].
Sleep deprivation causes inflammation, raises oxidative stress, and puts your body in a fight-or-flight state[*][*][*]. Chronic sleep deprivation is linked to premature death due to an elevated risk of heart disease, dementia, high blood pressure, arrhythmias, diabetes, obesity, impaired immune function and autoimmune diseases like lupus and rheumatoid arthritis[*][*][*][*].
A review that included over a million study participants found that short sleep duration increases the risk of death by 12% over time[*].
The effects of sleep deprivation get worse over time. Sleep deprivation reduces the function of your SCN (central circadian clock) by 40%, which weakens your natural body rhythms and affects digestion, wound repair, your immune system, and hormone production[*].
Sleep quantity and quality are as important as diet and exercise if you want to live a long, healthy life. By getting enough sleep and ensuring your sleep quality is high, you can perform better at work, improve your interpersonal relationships, and avoid the downsides of chronic sleep deprivation.
Health Benefits of Blue-Blocking Glasses
The good news is that more and more people are waking up to the harmful effects of artificial light at night. As a result, the popularity of blue-blocking glasses is on the rise.
As opposed to early blue blockers, which looked like welding goggles or 1980s sci-fi movie props, consumers now have access to stylish, comfortable blue blockers that preserve visual acuity while blocking sleep-disrupting short-wavelength blue and green light.
Mito Shades by MitoHQ have lightweight frames and high-impact, pigment-blended lenses that block 100% of blue and green light to improve your sleep and preserve your natural body rhythms. They also prevent eye strain and retinal damage associated with using digital devices.
If you wear Mito Shades at night to improve your sleep you’re less likely to suffer from insulin resistance, diabetes, high blood pressure, heart disease, cancer, and other chronic diseases[*][*][*][*].
Image credits: Illustration of the human brain showing the Cerebral Cortex, the Suprachiasmatic Nucleus, the Optic Chiasm, the Hypothalamus and the Pineal Gland by 黄雨伞 CC BY-SA 3.0. Light pollution, US focus, flat by Falchi et al., Science Advances, including Dan Duriscoe/NPS; Bob Meadows/NPS; Jakob Grothe/NPS contractor, and Matthew Price/CIRES and CU-Boulder CC BY 2.0 Flickr.