Blue light is essential for our health and wellbeing, but receiving it at the wrong times of day can be harmful to our health. With technology, blue light can be accessed 24 hours a day, and this is having an affect on our natural circadian rhythm.
Have you heard of blue light before?
When we think of blue light, we usually think of technology.
Studies have found that certain types of light, particularly blue light, have a significant impact on the body’s circadian rhythm (its 24-hour clock) and hormonal balance.
What is Blue Light?
Blue light is a colour on the visible light spectrum which our human eyes can pick up and see.
Before technology, the main source of blue light came from the sun.
Nowadays, blue light can be accessed 24 hours a day in forms such as digital screens (like TVs, smartphones, computers, laptops, tablets, and gaming systems), electronic devices, and LED and fluorescent lighting.
Before 1879, when Thomas Edison patented the electric light bulb, artificial lighting didn’t exist. After sunset, people relied on candles, fires, and lanterns for sources of light.
It was only 30 years ago when light was discovered to govern our internal clocks, and since then we’ve been learning more and more about blue light.
Artificial lighting contains blue wavelengths of light that are absent in light sources such as fires, candles, and lanterns. Blue light is essential for health and wellbeing, but receiving it at the wrong times of day can be harmful.
While research still continues, I believe more and more evidence will come to light sharing the health problems brought about by interruptions to the body’s natural circadian rhythm as a result of artificial light. Currently, the excessive use of artificial light and resulting lack of sleep has been linked to obesity, certain cancers, and an increased risk of heart disease.
The Impact of Light on Our Circadian Rhythm
The body is extremely clever. It has systems in place that help regulate circadian rhythm. It relies heavily on outside input (especially from blue light) to signal times it should be awake and times when it should be asleep.
The eye contains about 30,000+ cells which are able to detect blue light. When they sense this light, signals are sent to the brain to stop melatonin production. Melatonin is a hormone created by the body in response to darkness, and is needed for sleep. When we’re exposed to blue light at night, this can block melatonin production, affecting sleep.
Blue light wavelengths are found naturally in nature during the brightest parts of the day. These wavelengths are not found in other natural light sources such as fire, that would have been used at night before artificial light was created. If you’ve ever sat around a camp fire at night, you may have found it to be soothing, and it might have even made you a bit sleepy.
When it comes to blue light, it’s all about timing. Blue light during the day can be beneficial in many ways, such as:
- Promoting mood and alertness
- Sending certain signals to the body to maintain healthy weight and adrenal function
- Sending the correct signals to the brain for proper melatonin production
Doctors will sometimes use blue light therapy during certain times of the day to help improve sleep disorders, seasonal affective disorder (depression caused by lack of light), and other problems.
Blue light only really becomes a problem when the body is repeatedly exposed to it once the sun has gone down, particularly if it’s happening daily and over long periods of time. This interferes with the body’s natural rhythm, and signals to the brain to reduce melatonin production.
Sources of Blue Light Exposure
Sources of blue light include:
- Sunlight (the main source)
- Light bulbs and other sources of artificial lighting (LED bulbs are the main culprits).
- Electronics like phones, computers, TVs, etc.
Sunlight is a healthy source of natural blue light and it’s needed by the body for vitamin D conversion. It’s only really an issue when the body is exposed to blue light outside normal daylight hours.
In our modern day world, we’re exposed to blue light at times when we’re biologically ill-equipped to handle it, and this is having an affect on our hormone levels and hindering our quality of sleep.
The brain produces a tremendous amount of metabolic waste carrying out its many, many processes in the body. The glymphatic system, run by the glial cells, is responsible for cleaning up this waste in the brain. According to Shawn Stevenson in his book, Eat Smarter:
Though the glymphatic team does some light work throughout the day, it’s really the night-shift team that gives your brain a complete makeover while you’re sleeping. In fact, it appears that the glymphatic system is ten times more active putting in work while you sleep! A recent study published in Science Advances reported that during sleep (and especially deep sleep) your glymphatic system kicks into high gear, washing away wastes and toxic proteins.
Anything that impairs sleep, such as exposure to blue light at night just before bed, can disrupt the function of the glymphatic system and be a contributing factor behind disease and reduced cognitive function.
Artificial light causes the body to believe that it’s daytime, so the brain then suppresses the hormones required for sleep.
With more and more studies being released about the impacts blue light is having on sleep quality, more of us are now aware of the importance of restricting screen-time before bed. However, further research has shown that indoor lightbulbs, particularly LED bulbs, are also posing a problem, too.
It was written in the paper, Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans, that:
Being exposed to room light before going to bed suppressed melatonin production in 99% of individuals, as well as shortened the duration of melatonin production by around 90 minutes.
Does Red Light Impact Us the Same Way?
As it turns out, red light does not have the same effects blue light has on the body. As it turns out, it may be beneficial to us. It’s been shown to have benefits for hair, skin and joints (when delivered in forms such as Red Light Therapy).
As red light does not reduce melatonin levels like blue light, it’s a much better option to use as a light source in the evening.
Blue light blocking glasses, which block out most blue light, are a great alternative to help reduce blue light exposure at night. They aid in blocking out room lighting, as well as exposure to blue light from your phone, tablet, and computer.
How to Use Blue Light to Optimise Health
Timing your exposure to blue light throughout the day can make a huge difference. If we were to avoid blue light altogether it would be just as harmful (if not more so) to our health than simply being exposed to it at night.
Here are a few ways to use blue light to improve health:
- Blue light is essential during the day and it’s important that you expose yourself to natural sources of it daily to aid in proper functioning of the body’s natural circadian rhythm.
- As blue light suppresses melatonin at night, it’s recommended that you avoid blue light for two hours before going to bed. This can be done by avoiding screens and bright light in the home, and wearing blue light blocking glasses after sunset.
- Remove sources of artificial light (such as night lights, alarm clocks, lamps, etc.) in sleeping areas.
As always, this is not personal medical advice and we recommend that you talk with your doctor before trying or using any new products. I am not a doctor. All opinions expressed are my own personal thoughts and feelings of the products mentioned. Check with your doctor or health practitioner if you are uncertain about trying out any of the products, recipes or tips mentioned in this post.
What are some of the ways you avoid blue light during the evenings? Share in the comments below.
Lots of love,
What is Blue Light?. BluTech. Retrieved from http://blutechlenses.com/blog/blue-light/what-is-blue-light/
Wells, Katie. (January 11, 2018). Manipulating Blue Light to Improve Health. Wellness Mama. Retrieved from https://wellnessmama.com/91779/blue-light-improve-health/
Melatonin: What You Need To Know. (Updated: January 2021). NCCIH. Retrieved from https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know
Hill, Simon. (July 26, 2015). Is blue light keeping you up at night? We ask the experts. Digital Trends. Retrieved from https://www.digitaltrends.com/mobile/does-blue-light-ruin-sleep-we-ask-an-expert/
Stevenson, Shawn. (2020). Eat Smarter. Little, Brown Spark. 1290 Avenue of the Americas, New York, NY 10104. Print.