4 Blue Light Glasses Benefits on Sleep & How They Work
Blue light’s short wavelength is stimulatory, disrupting circadian rhythm by suppressing melatonin production at night. Quality blue light glasses effectively block this disruptive light, helping to improve sleep quality by allowing natural melatonin release.
What is Blue Light?
Blue light is a type of visible light with a short wavelength and high energy, ranging from 400 to 500 nanometers. It is one of the light frequencies emitted by the sun, which plays a crucial role in regulating human circadian rhythm, the sleep-wake cycle.
Beyond the sun, blue light is emitted by LED screens that most phones, computers, and tech devices have. Morning exposure to blue light is essential to stimulate wakefulness, while nighttime exposure is detrimental to sleep, stimulating the brain.
The wavelength of light determines its arousal level.
Shorter Wavelength Light (Stimulatory)
Shorter wavelength light is higher energy, being more stimulatory to the brain. Blue light falls into the spectrum of stimulating light, being between violet light (<450 nm) and yellow light (>570 nm).
The shorter the wavelength, the higher the stimulus. Shorter lights like gamma-rays, X-rays, or UV light are detrimental for humans, due to their intensity. They can penetrate deep into skin tissue, causing skin damage and aging.
Longer Wavelength Light (Relaxing)
The longer the wavelength, the less stimulating the light. Red or infrared light are longer wavelength, preferred at nighttime to reduce stress and stimulation. This is closely aligned to how the sun exerts its light. In the morning, there’s a higher spectrum of blue and violet light while in the evening as the sunset approaches, it shifts toward orange and red tones.
Red and infrared light exposure is linked to improved sleep quality. (1)
Blue Light: Morning vs. Evening
Blue light is a powerful regulator of circadian rhythm, playing a critical role in alertness, focus, and cognitive performance. Totally blocking blue light can have negative impact on health, as the body needs to be awake and stimulated in the morning, to rest and wind down in the evening.
Morning Blue Light: The Benefits
Exposure to blue light in the morning is essential for kickstarting the body’s internal clock and energizing the brain. Whether through natural sunlight, blue-emitting devices, or specialized glasses, morning blue light exposure
- Increases alertness by stimulating the noradrenergic system. (2) (3)
- Boosts cognitive performance, reaction times, and memory consolidation. (4) (5)
- Regulates the circadian rhythm, aligning wakefulness with daylight and promoting better sleep quality at night.
Morning exposure also suppresses melatonin and elevates cortisol levels, (6) providing the necessary stimulation to optimize energy and productivity throughout the day.
Evening Blue Light: The Drawbacks
In contrast, evening exposure to blue light disrupts the body’s natural preparation for sleep by
- Suppressing melatonin production, delaying sleep onset.
- Reducing slow-wave sleep in the first cycle and significantly decreasing REM sleep. (7)
Prolonged exposure to artificial blue light at night, such as from screens or LED lights, has been linked to a heightened risk of obesity, hypertension, and cardiovascular diseases, due to chronic circadian misalignment. (8) (9) (10)
What are the negatives of blue light?
Blue light can disrupt sleep, increase eye strain, and contribute to digital eye fatigue. Prolonged exposure at night can suppress melatonin, making it harder to fall asleep and negatively impacting sleep quality.
Is blue light harmful to your brain?
Blue light may not be directly harmful to the brain, but excessive exposure at night can interfere with the brain’s ability to regulate sleep, impair cognitive performance, and affect mood by disrupting the circadian rhythm.
Is blue light at night bad for you?
Yes, blue light at night can suppress melatonin production, delay sleep onset, and disrupt your circadian rhythm, leading to poor sleep quality and potentially long-term health issues like metabolic dysfunction.
The Importance of Sleep
Sleep is a fundamental process for maintaining overall health, supporting tissue repair, energy restoration, hormonal balance, and cognitive function. During sleep, the brain consolidates memories, clears waste products, and facilitates regeneration. (11) (12) Insufficient or poor-quality sleep disrupts these processes, impairing physical and mental health.
The National Sleep Foundation recommends 7–9 hours of sleep for adults and 7–8 hours for older adults. (13)
Sleep deprivation disrupts essential biological functions, increasing the risk of various health problems:
- Metabolic Dysfunction: Sleep insufficiency is linked to weight gain, impaired glycemic control, insulin resistance, diabetes, and obesity. Chronic sleep deprivation also contributes to cardiovascular dysfunction, inflammation, and hypertension. (14) (15) (16)
- Cognitive Impairment: Sleep disorders are associated with weakened cognition, memory deficits, mood instability, and a heightened risk of neurodegenerative conditions like Alzheimer’s disease. (17) (18) (19)
Overall, sleep is intricately tied to greater health, performance, and longevity. Prioritizing this natural regenerative process is essential to living longer, healthier lives.
Circadian Rhythm and Melatonin
The circadian rhythm, governed by the suprachiasmatic nucleus (SCN) in the hypothalamus, is the body’s internal clock that regulates physiological processes over a ~24-hour cycle. (20) Light exposure, especially in the blue wavelength, is a critical regulator of this rhythm.
Melatonin, a hormone produced by the pineal gland in response to darkness, promotes relaxation and deep sleep. (21) However, blue light exposure at night, such as from screens or LED lights, suppresses melatonin production by activating intrinsically photosensitive retinal ganglion cells (ipRGCs). (22) (26) These cells release melanopsin, signaling daytime to the brain and disrupting the sleep-wake cycle.
Studies show that blue light exposure 1–2 hours before bedtime can suppress melatonin by up to 38%, delaying sleep onset and reducing sleep quality. (23) Long-term disruption of melatonin rhythms is linked to metabolic issues, glucose intolerance, and impaired recovery. (24) (25)
Does blue light affect circadian rhythm?
Yes, blue light stimulates stress hormones like cortisol and adrenaline which increase productivity in the morning. However, at nighttime, blue light disrupts melatonin production which delays sleep onset and impairs sleep quality. It’s essential to wake up properly in the morning, activate, and be productive. Cutting it towards the nighttime is a smart strategy to de-stimulate the brain and ease off to sleep.
Does blue light interfere with melatonin?
Yes, blue light interferes with melatonin production by stimulating light-sensitive cells in the eye, which inhibits the release of melatonin, making it harder to fall asleep.
Can melatonin mess with circadian rhythm?
Yes, if melatonin is taken at the wrong time, it can shift the circadian rhythm, either delaying sleep or causing disruptions in the sleep-wake cycle. Most supplements offer very high (3-10 mg) and potent doses of melatonin which are supraphysiological, meaning the body can develop a tolerance to it and reduce its natural production.
What is the best night light for circadian rhythm?
The best night light for circadian rhythm is one that emits warm, dim light, such as amber or red tones, as these wavelengths have minimal impact on melatonin production and circadian rhythm. Candles, red light panels, or infrared bulbs are great tools to set a healthier, more sleep-conducive nighttime lighting environment.
Blue Light Glasses Benefits
Blue blocking glasses typically have amber-shade, which doesn’t prove their effectiveness. Not all amber-shade glasses block blue light and clear glasses can block blue light as well. Very cheap glasses are typically not recommended, quality glasses from an optics shop are.
Blue blockers have been shown to improve sleep quality, sleep duration, and mood. (27) (28) Studies indicate that they can reduce sleep onset latency, making them especially helpful for those with irregular schedules, sleep disorders, or frequent travelers. (28)
The effect is due to their ability to reduce melatonin suppression from blue light exposure. (29)
Prolonged exposure to blue light from screens can cause eye fatigue, dryness, and potentially contribute to age-related macular degeneration (AMD), although aging remains the primary factor. (30)
Wearing blue-blocking glasses can improve sleep quality, melatonin levels, and sleep duration. (31) These results suggest that blue blockers not only protect the eyes but may also enhance sleep by reducing light receptor stimulation.
Wearing blue-blocking glasses a few hours before bedtime to prevent melatonin suppression from artificial light seems effective. This simple practice can improve sleep quality, reduce the time it takes to fall asleep, and even boost mood before sleep.
What are the benefits of wearing anti blue light glasses?
Wearing anti-blue light glasses may help reduce eye strain, improve sleep quality by blocking melatonin suppression, and help reduce the negative effects of prolonged screen exposure, especially at night.
Do blue light blocking glasses really work?
Yes, blue light blocking glasses work by reducing blue light exposure, which can prevent the suppression of melatonin, improve sleep onset, and reduce eye strain associated with prolonged screen time. However, only real, high-quality blue light glasses from an optical shop are recommended.
Is it OK to wear blue light blocking glasses all the time?
No. Wearing blue blockers all the time can disrupt the circadian rhythm as the brain and the body need blue light in the morning and throughout the day. This increases alertness, focus, and productivity. It’s an essential stimulus to help the body reset later on, as the night approaches.
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