Blue Light: Is It Keeping Us Up at Night?

Have you heard about blue light before? It may have been in regards to technology and how staring at a screen for too long, just before going to bed, can impact sleep quality.

Light and sleep are two of the most under-valued, under-utilised tools for improving health, BUT, improper management of the two leads to many health problems. Studies have shown that certain types of light, particularly blue light, have a significant impact on our circadian rhythms (our 24-hour internal body clock) and hormone 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! Now we’ve brought blue light into our homes 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.

Since then, artificial lighting has slowly become more and more common, with it skyrocketing over the past century as a result of the boom in technology where we’ve switched from using candlelight to mobile phone screens. In fact, it was only 30 years ago when light was discovered to govern our internal clocks, and since then we’ve been slowly learning more and more about blue light.

As research continues, I believe more and more evidence will arise showing that interruptions in our natural circadian rhythms from artificial light will be partly to blame for many of the health problems we’re seeing today. Currently, it has been found that the excessive use of artificial light and the resulting lack of sleep may be linked to obesity, certain cancers, and an increased risk of heart disease.

Artificial lighting contains blue wavelengths of light that are absent in light sources such as fires, candles, and lanterns. Blue light has been shown to improve mood, energy and alertness (naturally, as when the sun would rise it would trigger our natural body clock to wake us up), and is important for health and wellbeing. BUT, receiving it at the wrong times of day can be harmful.

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 that of blue light) to signal times the body 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 naturally found in nature during the brightest parts of the day. These wavelengths are not found in other natural light sources, like 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 even felt a bit sleepy. This is largely due to its lack of blue light.

Earth Hour 2019; No lights, no electricity, for 1 hour <3

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.

Fun fact: Doctors have started using 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 a person is repeatedly exposed to it once the sun has gone down, particularly if it’s happening daily, over long periods of time. This interferes with the body’s natural rhythms 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 beneficial to be exposed to blue light during the hours of the day (when there’s sunlight around).

Now, because of artificial forms of blue light, we’re now exposed to it at times when we’re biologically ill-equipped to handle it, which is affecting our hormone levels and decreasing our sleep quality.

What’s happening is this 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 has on our sleep quality, more people are now aware about restricting screen-time before bed, which is wonderful! However, further research has shown that indoor lightbulbs, particularly LED bulbs, may also be posing a problem.

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?

It turns out red light does not have the same effects as blue light, but in actual fact, 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 another alternative for avoiding blue light at night. They aid in blocking out room lighting, as well as exposure to blue light from your phone, tablet, and computer.

These blue light blocking glasses are from Baxter Blue, and filter out as much as 80% of the highest energy wavelengths known to cause digital-eye-strain.

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 just being exposed to blue light at night. Here are a few ways to use blue light to improve our health:

  1. 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.
  2. As blue light suppresses melatonin at night, it’s recommended that you avoid blue light for 2 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.
  3. Remove sources of artificial light (such as night lights, alarm clocks, lamps, etc.) in sleep areas.
I always wear my blue light blocking glasses now whenever I’m working on the computer, on my phone, in front of the TV, or on any other screen to help protect my eyes. I also wear them at night to help reduce exposure to blue light in the evenings.

As always, this is not personal medical advice and we recommend that you talk with your doctor before trying or using any new products. It’s important to check with a doctor before taking this or any new product, especially if taking any other medicine or supplement or if pregnant or nursing. Be sure to check ingredients to make sure there is no risk of an allergic reaction to it.

What are some of the ways you avoid blue light during the evening? Share in the comments.

Lots of love,

🖤 Vanessa


What is Blue Light?. BluTech. Retrieved from

Wells, Katie. (January 11, 2018). Manipulating Blue Light to Improve Health. Wellness Mama. Retrieved from

Melatonin: What You Need To Know. (Updated: January 2021). NCCIH. Retrieved from

Hill, Simon. (July 26, 2015). Is blue light keeping you up at night? We ask the experts. Digital Trends. Retrieved from