White light and all the colors that make it up (red, orange, yellow, green, cyan, blue and violet) have many different effects on humans, some colors have greater effects on the human body than others, among the colored lights, blue and green light are the most studied and their effects on mental health have been widely described.
How could blue and green light affect you in such a way that it generates anxiety and stress? In this article we will review the relation between blue and green light, anxiety, stress, depression, and sleep problems (1).
How Can Blue Light Affect My Hormones?
Much is known about the effect of blue and green light on the circadian rhythm, but lately the effect of these light spectra on other systems has been studied, such as the endocrine system, which is in charge of producing and regulating the hormones that govern our body.
Humans have become accustomed to having artificial light all the time, day and night, on our phones, our light bulbs, everything is artificial light, so we are in constant exposure to it. Prolonged exposure increases the levels of cortisol and adrenaline, hormones related to normal body function, but if they are produced in excess, problems will start surface (3).
Specifically overexposure blue and green light cause these stress hormones to become abnormally elevated, initially manifesting as physical alterations for a person, but these hormones not only have an effect on the body but also on the brain leading to mental imbalance, and this ultimately, disorders such as anxiety and / or depression develop (3).
The alteration in the production cycle of hormones, mainly, adrenaline and cortisol can contribute to the development of major mental disorders such as anxiety and depression (3).
Hormonal Balance and Mental Balance
All humans have a biological clock, called the circadian rhythm (circa = approximately, dian = day), that is controlled by many mechanisms, but mainly by a hormone called melatonin, which increases at night and decreases during the day, as is well known, light, especially blue light modifies the secretion of this hormone, causing it to be produced irregularly during the day or even not to be produced at all, so the circadian rhythm is altered (1).
In the body, the production of a large number of hormones is regulated by the circadian rhythm, some hormones have to be secreted more in the morning and others more at night, all this not only to maintain a physical balance but to maintain a mental balance (1).
The mental balance and the hormonal balance regulate each other, the mental balance is multifactorial, but the main factor that maintains the balance of the cerebral functions is; sleeping properly, good or bad night sleep is directly related to exposure to blue light, as previously stated, blue light decreases melatonin secretion, therefore prolonged exposure to it decreases sleep, keeping the body in constant alertness (4).
If a person does not sleep well, it begins to present problems such as; mood disturbances, stress, and remains in that constant state of alert, which generates mental and physical fatigue, in this sense, only the fact of not sleeping well will contribute to mental disorders (4).
Additionally, not sleeping well, will alter the entire circadian rhythm, so that all the secretion of hormones (mainly cortisol and adrenaline) will be altered. This alteration usually involves the increase of these molecules throughout the body, causing them to have an exaggerated effect, thus perpetuating the previously established alteration of the mental state (3, 4).
Hormonal Alteration and Anxious Disorders
Anxiety is defined as the irrational fear towards a situation, person, or object that does not represent any danger, or otherwise, the person is prepared for action, the reason why it is found with accelerated heart rate and agitated mind (5).
Anxiety disorders are one of the most common mental disorders in the overall population. In the US 10 to 25% of the population suffers from anxiety (6).
Continuous exposure to blue light and sleep disturbances like insomnia are deeply related to anxiety disorders, studies indicate that anxiety disorders can be found in about 24 to 36% of subjects with insomnia (6).
This means that a state of anxiety can be generated by simply not sleeping well, and if we add the fact that not sleeping accordingly increases the secretion of adrenaline, which is the hormone that prepares us for action, we create a vicious cycle, where the person becomes agitated or altered because they do not sleep well, this increases the secretion of adrenaline and cortisol, so the heart rate increases, the respiratory rate increases, your mind is ready for action, so anxiety increases even further (7).
Other Than Anxiety And Stress, Can Blue Light Cause Depression?
The short answer is Yes. Continuous exposure to blue light can increase the cortisol levels in our body as we previously said, so if we also add that we are receiving blue light also at nighttime it completely alters the circadian rhythm, maintaining an alert state even at night, favoring insomnia, increasing and altering the production of hormones like adrenaline, dopamine, serotonin and cortisol, all of these related with mental illness like depression and anxiety (8, 9).
The relation between sleep and depression is quite important, about three-quarters of people with depression also have sleep disturbances (8).
Cortisol has very specific functions in the human body, it is secreted continuously to maintain the balance of the body, but it is also secreted in situations of “fight or flight” to prepare the body for these actions, so if it is secreted in an exaggerated way when the person is not in these dangerous situations, it can have important physical repercussions (Arterial Hypertension, Diabetes, Cardiovascular disorders, among others). Also, its increased secretion contributes to generating a state of stress, since the hormone cortisol is considered the “stress molecule” (3, 8).
The constant and altered secretion of cortisol is the main cause of chronic stress, and chronic stress is an important cause of insomnia, making this another toxic cycle for humans. Excessive artificial light induces poor sleep, poor sleep leads to stress, stress brings insomnia, so this will cause people to sleep badly, and all of this is going to perpetuate. The vicious cycle that has just been described is caused by the excessive exposure to blue and green light and the alteration in the secretion of melatonin that this exposure produces (3, 8, 9).
How Can I Balance My Circadian Rhythm and My Stress Levels?
After reading this article, this may be your main question, how to avoid these mental disorders. The answer is very simple.
Decreasing exposure to blue and green light. But how is this accomplished? Exposure to blue light has been constant since prehistoric times, due to our exposure to the sun, but the presence of blue light in our lives has increased exponentially due to advent of technological equipment such as light bulbs, cell phones, tablets, televisions, so we have to take several measures to reduce the blue and green light in our lives (10, 11, 12, 13).
During the day we can decrease the exposure to blue light using blue light blocking glasses that filter this harmful wavelengths of light, this will allow melatonin secretion to increase during the day until it reaches its peak at night, but to keep it at night, we have to completely eliminate our exposure to blue and green light, so we have to modify the light bulbs in our bedrooms, use protective screen filters for our phones, and finally use light blocking sleep masks to have a deep and sustained sleep (10, 11, 12, 13).
Here are our key recommendations to mitigate over exposure the artificial light which could be one of the root causes of your high stress, anxiety, and depression:
Filter Blue light During The Day
Our modern lifestyles now see us spend most of the day indoors under artificial LED and fluorescent lighting whilst looking at screens and devices. This creates abnormally high exposure to harmful blue light wavelengths which are much higher than we would receive naturally outdoors from the sun. These high levels of blue light cause an increase in our stress hormones cortisol and adrenaline which leave us feeling highly stressed, irritable, and anxious.
The best way to combat this issue during the day is to use specifically designed blue light computer glasses that filter blue light by 50%. This allows enough healthy blue light through to keep you awake, alert, and motivated whilst filtering out all the harmful wavelengths. A key feature required with computer glasses is they must target 455nm which is the peak wavelength of light emitted by screens and lighting shown to cause anxiety and depression. Most computer glasses available only filter blue light up to 430nm and none at all at 455nm, so be sure to do your homework before purchasing if you want to have adequate protection.
Block Blue Light At Night
Once the sun has set even the smallest amount of blue light exposure will send a wakefulness signal to the brain, so instead of winding down and feeling relaxed in the evening, this constant day time signal will leave you feeling anxious, wired, and alert. It is essential to use a set of quality blue light blocking glasses that are verified to block all blue light. This will then allow optimal levels of the sleep hormone melatonin which is responsible for sleep quality. Quality sleep is essential for maintaining good mental health, and lack of sleep will eventually lead to anxiety and depression disorders.
Use Healthy Flicker Free Lighting
All conventional LED and fluorescent lighting emits harmful flicker. Flicker is when the light pulses on and off 100’s of times a second. While this is not visible to the human eye, the brain is able to recognise this very fast flashing and pulsing light. Being exposed to this flickering light creates high levels of stress to the brain as it needs to work extremely hard to process the rapidly changing light signals. This then leads to high levels of adrenaline and cortisol, which in-turn leaves people feeling irritable and anxious.
Using flicker free lighting is the only way to mitigate these harmful and stressful effects from lighting. We have worked extremely hard to develop a range of light bulbs, book lights, lamps, and night lights which not only eliminate this harmful flicker but also eliminate the blue light spectrum. This is the healthiest lighting available.
Sleep In Complete Darkness with a Light Blocking Sleep Mask
Light pollution can be simply unavoidable for many of us in today’s modern world. Street lights, car headlights, neighbors house lights all are responsible for polluting your sleeping environment with varying levels of artificial light. When sleeping our brains expect complete darkness, any amount of light while sleeping will lead to lower levels of melatonin and higher levels of cortisol and adrenaline, which in-turn will impact sleep quality.
Using a 100% light blocking sleep mask will allow your brain to experience complete darkness through out the night which will keep melatonin levels naturally high and stress levels low.
Final Thoughts
Although stress and anxiety are multifactorial diseases, the importance of light on these pathologies has increased over the years, thus demonstrating direct implications of blue and green light in the development of these conditions, also there are lot of studies that describe the implication of light in generating sleep disturbances and perpetuating the vicious cycle that we mentioned earlier.
The over exposure to artificial light not only compromises people’s mental balance, it also affects them physically, it can trigger high blood pressure, insulin resistance, heart attacks, strokes, among others, so it is important to know how to control them, but above all, how to prevent them.
The world around us is beautiful, but we are giving excessive use to technological objects and devices, so it is important to take adequate preventive measures, small changes in our lives can lead to large modifications, therefore reducing exposure to blue and green light can improve our sleep, decrease stress, anxiety, thus improving our quality of life.
Resources
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- American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (Fifth ed.). Arlington, VA: American Psychiatric Publishing. p. 189. ISBN 978-0-89042-555-8.
- Cox R, Olatunji B. A systematic review of sleep disturbance in anxiety and related disorders. Journal of Anxiety Disorders. 2016; 37: 104-129. Shechter, A ., Kim, EW, St-Onge, MP, & Westwood, AJ (2018).)
- Oh C, Kim H, Na H, Cho K, Chu M. The Effect of Anxiety and Depression on Sleep Quality of Individuals With High Risk for Insomnia: A Population-Based Study. Frontiers in Neurology. 2019;10.
- Institute of Medicine (US) Committee on Sleep Medicine and Research; Colten HR, Altevogt BM, editors. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Washington (DC): National Academies Press (US); 2006. 3, Extent and Health Consequences of Chronic Sleep Loss and Sleep Disorders. Available from:
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- Cox R, Olatunji B. A systematic review of sleep disturbance in anxiety and related disorders. Journal of Anxiety Disorders. 2016;37:104-129.Shechter, A., Kim, E. W., St-Onge, M. P., & Westwood, A. J. (2018).
- Shechter A, Kim E, St-Onge M, Westwood A. Blocking nocturnal blue light for insomnia: A randomized controlled trial. Journal of Psychiatric Research. 2018;96:196-202.
- Lawrenson J, Hull C, Downie L. The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle: a systematic review of the literature. Ophthalmic and Physiological Optics. 2017;37(6):644-654.
- Kimberly B, James R. P. AMBER LENSES TO BLOCK BLUE LIGHT AND IMPROVE SLEEP: A RANDOMIZED TRIAL. Chronobiology International. 2009;26(8):1602-1612.
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