One of the major advancements in human history was the invention of the lightbulb. I am sure everyone remembers learning about this monumental moment a long time ago in elementary school. Before the invention of the light bulb people had to rely on candle light or some kind of gas lighting. These forms of light are inherently dangerous, as open flames and gas can easily cause fires, especially 100 years ago where flame retardant technology was not as good as it is today. In addition candle and gas lighting was not very bright, so it required many more candles/gas lights to provide enough light to be useful. The light bulb provided a lot of light in a much safer manner.

When the lightbulb was invented it essentially allowed us to extend our days. Before the lightbulb, when the sun went down we either went to bed or sat by a fire and went to bed soon after. This is how we evolved as humans for 100’s of thousands of years, in rhythm with the rising and setting of the sun. When the lightbulb came along we were no longer held captive by the sun, we could extend our work days, as well as our social lives, well into the evening and even the next day. This obviously had positive impacts on our economy as well as allowed us more flexibility socially. Think of all the night time and early morning activities that have been made possible by the lightbulb.

I don’t think, when Thomas Edison invented the lightbulb, that anyone considered the impact on our health. Like I said, we followed the rhythm of the sun for 100’s of thousands of years. Now all of a sudden, in the past 100+ years, we could break free of the sun’s constraints. So what impact does light after dark have on our health?

Timing Is Everything

A standard light bulb produces a type of light called blue light. Where do we find blue light naturally? As you might expect, blue light is emitted by the sun. Evolution is clever in that when our bodies detect blue light it triggers certain hormonal changes that signal we should be awake and active.

When the sun is up and sunlight hits our skin and enters our eyes, the blue light from the sun triggers our body to down regulate a hormone called melatonin and upregulate a hormone called cortisol. Melatonin is a hormone that is responsible for us falling and staying asleep. Cortisol is a hormone that gives us energy and provides us that drive to get going in the morning after we wake up.

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Since light bulbs continue to emit blue light even after the sun has set it can confuse our bodies into thinking the sun is still up. This will suppress the natural production of melatonin and keep the production of cortisol elevated. This in turn can disrupt our sleep^[1] and can contribute to a number of chronic diseases including type 2 diabetes^[2], depression^[3], cardiovascular disease^[4], and obesity^[5].

The Right Light At the Right Time

“In the right light, at the right time, everything is extraordinary” – Aaron Rose

Since the sun and fire are no longer our only sources of light we need to make sure we are getting the right type of light at the right time to ensure we do not disrupt our bodies natural hormone cycle. Here are some simple steps you can take to ensure you are aligning your light exposure with what your body would naturally expect.

Get Natural Light First Thing In The Morning

Our body expects to get sunlight when we wake up. Unfortunately, it is not uncommon for us to spend nearly the entire day inside without sunlight ever hitting our bodies, especially during the winter months . It is important to try and get some light exposure soon after waking up to suppress melatonin and up-regulate cortisol. If at all possible, try and get out in the sun first thing in the morning. If that is not possible there are some artificial sources of light called light therapy boxes that can simulate natural sunlight. You can find these devices on Amazon, but of course the real thing (aka the sun) is always best.

Use Blue Light Blocking Glasses

When the sun sets where you live you need to try and limit your blue light exposure in order to help promote melatonin production and down regulate cortisol. This can be very tough to do in today’s world. We not only have light bulbs that emit blue light but we have TV’s, smart phones, tablets, all kinds of other electronic devices emitting light. Even the light from your alarm clock can be enough to suppress melatonin. The easiest way to limit your blue light exposure is through the use of blue light blocking glasses. These have become quite popular as of late and there are many options to choose from. I personally like the brand BluBlox which has many stylish glasses to choose from. Just throw on your glasses once the sun goes down and it will really help block a lot of the blue light.

Remove Blue Light On Your Devices

Lots of device manufacturers are also starting to build in technology that helps block blue light. Both iPhone and Android devices have the ability to automatically shift the light spectrum they emit at night. Apple computers as well as PCs also have this functionality built in. You can even install software on your computer to remove the blue light. I suggest everyone look into at least enabling these features on their phones, tablets, and computers as it is an easy win for removing blue light. Of course the ultimate goal would be to not use any devices at all, but I understand that can be a difficult transition at first.

Other Hacks

You can go further and switch out the light bulbs in your house to ones that don’t emit blue light, put filters on your TV which take out the blue light, put tape over lights on TVs, alarm clocks, etc. At the end of the day how far you have to go to remove blue light at night is going to depend on how sensitive you are. Some people see drastic differences in sleep, others not so much.

Now Take Action

Now you know the importance of light and its effects on our health, so now it is time for you to take action! At the very least get some blue light blocking glasses and adjust your phone/tablet/computer to remove blue light at night and get some kind of sunlight in the morning. If you are not doing these things today, I am almost certain you will see an improvement in your sleep and therefore an improvement in your health moving forward.

1. (2016, January 24). Effects of blue light on the circadian system and eye physiology. Retrieved April 24, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/ ↑

2. (2006, September 18). Role of sleep duration and quality in the risk and severity of …. Retrieved April 24, 2020, from https://www.ncbi.nlm.nih.gov/pubmed/16983057 ↑

3. (n.d.). Symptoms of depression in individuals with obstructive sleep …. Retrieved April 24, 2020, from https://www.ncbi.nlm.nih.gov/pubmed/16162722 ↑

4. (n.d.). Inflammatory aspects of sleep apnea and their cardiovascular …. Retrieved April 24, 2020, from https://www.ncbi.nlm.nih.gov/pubmed/16466124 ↑

5. (n.d.). The link between short sleep duration and obesity: we should …. Retrieved April 24, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2082964/ ↑