Is too much blue light from electronic devices bad news?
The answer is YES.
In this article we’ll look at how artificial blue light exposure can lead to circadian disruption, anxiety, stress and mood disturbances!
What is Blue Light?
Light has profound effects on your mental and physical well-being.
And different colours of light have different effects!
For instance, green light therapy may help reduce pain-related anxiety, and red/near-infrared light boosts ATP (energy) production and has anti-inflammatory effects.
So, what’s the deal with blue light?!
Well…
Light is electromagnetic radiation, a form of energy flowing through space.
“Visible light” are the wavelengths in the electromagnetic spectrum which the human eye can detect – spanning from ultraviolet/blue (400 nm) to red (700 nm) wavelengths:
And as you can see, blue light is a natural part of the visible light spectrum!
Now, blue light can come from two different sources:
- Natural sunlight, our main source of blue light exposure, which we get from spending time outdoors during daytime.
- Artificial blue light emitted from our electronic devices, e.g laptops, tablets, smartphones, computer monitors and TVs, as well as fluorescent and LED lights.
Blue light from the sun is NOT a problem in reasonable quantities, in fact, light therapy that mimics natural sunlight has been used to treat seasonal affective disorder (SAD) during winter months.
(Morning sunlight can also help ‘set circadian rhythms’ and improve sleep quality which we will look at later!)
It is the latter form of artificial blue light that is harmful…
Blue Light Overexposure?
Before electricity was invented, humans were exposed to natural blue light from the sun during daytime.
And after sunset, it got pretty dark.
There were no smartphones, LED lights or other electronic devices around emitting artificial blue light during nighttime; instead we lit candles and fireplaces to generate warmth and light (fire emits calming red/infrared wavelengths).
In stark contrast, modern life often involves working indoors under artificial LED and fluorescent lights, whilst staring at blue light emitting screens all day long.
In other words, we are being flooded with artificial blue light 24/7.
And herein lies the crux of matter…
This overexposure to unnatural blue light is a major stressor for the body!
Essentially, it has similar effects on the body as any other perceived threat, and can likewise trigger a stress response with an increase in cortisol and adrenaline levels, irritability, anxiety and fear.
And one of the main ways through which blue light contributes to stress and anxiety is by messing up circadian rhythms (and your beauty sleep)…
How Does Blue Light Exposure Disrupt Circadian Rhythms?
First of all… what are circadian rhythms?
Every single cell in your body has its own biological clock that “keeps track” of the 24-hour day and night, or light and dark cycle. These biological clocks create circadian rhythms that repeat every 24 hours and regulate the sleep–wake cycle.
Circadian rhythms also regulate the synthesis pattern of important hormones in the body, such as the ‘sleep hormone’ melatonin produced by the pineal gland in the brain.
When it gets DARK → the pineal gland starts producing melatonin.
And when it gets LIGHT → production stops again.
Meaning:
Melatonin synchronises the sleep-wake cycle with day and night, and it helps you sleep during nighttime!
Blue Light Messes Up Melatonin Secretion
Light is one of the most important ‘time setters’ or environmental cues that entrain circadian rhythms.
There are even specific blue light photoreceptors on the retina that directly communicate with the brain’s master circadian clock (SCN).
Blue light hitting the retina during daytime is beneficial and helps to promote cognitive function, alertness and well-being; and an ABSENCE of blue light during nighttime is equally important for melatonin secretion and good quality sleep!
You can guess where this is heading…
Artificial (blue) light exposure during nighttime messes up your circadian rhythms big-time:
It has been shown to suppress melatonin synthesis (by up to 71.4%!), increase alertness and negatively impact sleep quality/quantity.
This disruption, or shifting, of circadian rhythms by artificial light is NO BUENO for your (mental) health.
We know that circadian disruption messes up your sleep, but it’s also linked with worsened metabolic, cardiovascular and psychological health. And the effect is dose-dependent, i.e it gets worse with longer duration and with exposure later during night.
Even very low levels of blue light in the evening via electronic devices has a potent disruptive effect on circadian rhythms!
As I hinted at already, not getting enough sunlight (blue light) during winter months can ALSO shift circadian rhythms! Meaning, if you can, try to get out in the morning or daytime sun to ‘set’ or entrain proper circadian rhythms. This will help you to sleep better during nighttime!
Blue Light Wrecks Your Sleep & Spikes Stress Hormones
Getting a good night’s sleep helps immensely with reducing stress and anxiety levels.
It really does make a night and day difference.
(…No pun intended).
And as we now know, whether you get a good night’s sleep or not is directly related to blue light exposure.
Continuous exposure to blue light, sleep problems and anxiety are connected in a vicious circle — what happens when you stay up late and stare at blue-light emitting screens?
After sunset, even small amounts of blue light is going to send a “it’s morning now, WAKE UP!” signal to the brain, which will make you feel stressed out, wired and unable to relax.
Here’s the ensuing chain of events:
- nighttime blue light exposure →
- circadian rhythms, melatonin secretion are disrupted →
- you don’t sleep well →
- there is an increase in hypothalamic–pituitary–adrenal (HPA) axis activity and a rise in the stress hormones cortisol →
- you feel stressed out, agitated and more alert →
- this makes it difficult to sleep and you spend the night looking at your smartphone instead →
And so on and so forth.
Of course stress, anxiety and depression are multifactorial issues, but too much blue light exposure alone is enough to mess up your sleeping patterns and make you feel quite terrible!
Blue Light – A Stress Hormone Double Whammy
Moreover…
Blue light, and bright white light, have stimulatory effects on the hypothalamic-pituitary-adrenal (HPA) axis activity (in comparison to dim light and red light), which further contributes to elevated levels of cortisol.
This is not necessarily a bad thing as you do want a cortisol spike during the morning hours; cortisol also follows a circadian rhythm and peaks when you wake up in the morning and should fall over the course of the day.
But it is not a good thing to have cortisol levels spiking at 9 PM when you are soon going to sleep!
I also found this study from 1977 which demonstrated that increasing intensity of artificial light caused “light stress” in humans, with an increased production of cortisol.
To summarize:
Through different mechanisms blue light increases your levels of stress hormones like cortisol… not good!
How To Mitigate Harmful Effects of Blue Light Exposure?
The answer is simple…
Get rid of blue light!
This will allow healthy levels of the sleepy hormone melatonin to be secreted during the evening, and you will sleep like a baby! And it’ll probably lower your stress and anxiety levels by at least 168%… I reckon. 🙂
You have to find ways to reduce your exposure to ALL artificial blue light, including: LED and fluorescent lights, smartphones, tablets, TVs, your neighbour’s TV, outdoor lighting, and so on.
This may seem like an insurmountable task, but here are 8 practical tips on how to do this:
- Switch out the fluorescent LED lights in your home for old-fashioned incandescent lightbulbs. Or at least in your bedroom! These are not as energy-efficient but they produce a lot less blue light and more red light wavelengths. One study showed that red light can actually help improve sleep and melatonin levels.
- Avoid looking at your phone, tablet, TV or laptop at least 2 hours before bed.
- QUIT SOCIAL MEDIA.
- Install apps that filter out the blue wavelength on your electronic devices. I use f.lux for my computer and some random app for my phone!
- Another alternative, if you don’t mind looking like a “nerd” or a “biohacker”, is to start wearing blue-blocking glasses during evenings. These glasses are RED and look a little silly, but they are designed to filter out the harmful blue light wavelengths emitted by screens!
- Or try wearing GREEN glasses – one study showed that these reduce pain-related anxiety in patients with fibromyalgia!
- Get out during morning/daytime and expose yourself to natural blue light! This will ‘set’ or entrain your circadian rhythms, and improve your mood during daytime.
- Change your environment, quit your job and spend more time outside in nature (may not be practical for most people).
In summary:
Blue light is not only detrimental to your mental health; it’s a stressor that comes with a wide variety of negative health consequences (including damaging your retinal cells!), which is why you probably want to minimize artificial light exposure!
The measures above will help protect you from the dangers of blue lights, and decrease stress and anxiety levels.
Cheers, let me know how you avoid blue light dangers in the comments! 🙂
And make sure to share this with anyone who watches Youtube on their smartphone before bedtime!