Humans spend about a third of their lives sleeping. Getting enough quality sleep is critical for our concentration, cognitive function, and overall health. We used to have a natural sleep cycle because the only light source was the sun. Today, things are very different. We have lights wherever we go throughout the entire night. Moreover, many people use a smartphone and watch TV before going to bed. All of these practices bombard your eyes with blue light, which negatively affects your sleep quality. Long-term exposure can lead to further and more serious complications. The impact of light on our circadian cycle The circadian cycle is a biological process that regulates the sleep-wake cycle and tells our brain when it's time to sleep. It's a built-in clock that depends on the 24-hour day/night cycle. Everyone has a different clock, but most of us go to sleep when there's not enough light. Our brains can tell that it's time to sleep when there's not enough light and a cascade of biological occurrences prepare us for that. Since we live in the modern age, we always have plenty of light. That light makes it into our eyes, and they tell the brain that it's still not time to sleep. The light sensors in our eyes are very powerful, and if they get too much or too little light, we can quite easily experience sleep problems or disruption. Some experiments proved that the circadian cycle tends to drift for about half an hour every day in total darkness. When you're exposed to too much bright light, the cycle is also damaged, leading to bad sleep quality and long-term damage.

Why is blue light an issue?

Blue light is just one element naturally found in light. The blue wavelengths are responsible for keeping our brains in working order. Blue light improves concentration, mood, and reaction times. However, our brain's internal clocks need a break from blue light, so they keep shutting down when the night comes. The problem starts with electronic devices that produce light. That includes smartphones, monitors, TV sets, and tablets. Screens have high levels of blue light that tells our brains that it's still daylight. That interrupts the natural circadian cycle, kicking our brains into overdrive, rather than going to sleep. Some studies suggested that long exposure to blue light suppresses the natural production of melatonin in our brains, leading to bad sleep quality, and other health complications in the long run.

Common blue light sources

There is no easier way to put it than saying that blue light is everywhere. You are constantly exposed to blue light during the day when the sun is up. All man-made light sources also emit blue light. The most common blue light sources are:
  • Computer screens
  • Electronic notebooks
  • Smartphones
  • LED TVs
  • Tablets
  • Fluorescent light bulbs
  • LED bulbs
Man-made blue light sources emit much weaker frequencies than the sun, but if your eyes are under constant exposure, you could end up suffering from all kinds of issues, eye strain being the least of your worries.

Lighting as a public health issue

We can't even imagine living in a world without night lights, but the truth is that we need darkness for our bodies to function correctly. Electric lighting, no matter what type, disrupts our circadian rhythm, leading to serious diseases over time. Some studies found links between lighting and cancer, obesity, and diabetes. Constant exposure to light affects our hormone levels leading to melatonin reduction. Low melatonin levels increase the probability of getting breast cancer and other forms of this disease. We are not designed to be bombarded with light all day long, primarily LED lights. Our brains need time to relax and start the circadian cycle on time. That's why exposure to light before going to bed leads to sleep problems and other health issues.

Bad habits

Since we can't completely remove exposure to blue light, it's essential to understand that too much exposure can lead to serious health issues. Modern society forces all kinds of bad habits on everyone, without ever saying anything about the consequences. Here are some bad habits you should correct to improve your circadian cycle and sleep quality:

- Spending too much time on mobile devices

Studies proved that about 3/4 of teens ages between 12 and 17 spend at least two hours watching TV or playing computer games. About 20% spend over four hours exposed to blue light every day. If you're doing the same, you should try to minimize exposure to blue light as much as possible.

- Watching TV before bed

Many of us watch TV just before we go to sleep thinking that it makes us sleepy. The reality is totally the opposite. Watching TV before sleeping wakes up your brain, making it harder to fall asleep. Even when you finally do fall asleep, the sleep quality will be affected.

- Installing LED lights everywhere

LED lights are very popular in the past few years because they don't need a lot of power to emit light. Installing LED lights all over your home can help you cut down on the electricity bills, but they won't help you sleep better. Your eyes will be under constant threat from the blue light, and that's never a good thing.


So, what can you do to prevent blue light exposure? Well, you can take the TV out of your bedroom for starters. It would be best if you also stopped staring at your smartphone all day long, especially when it gets dark. If you can, install new light bulbs in your home. Choose the ones closer to the red light spectrum. So-called "warm" lights are the best option. If you can't cut down on your screen time, consider buying blue light glasses. These glasses are designed to block blue light from entering your eyes, protecting your natural circadian cycle. If you spend a lot of time working on your computer, these glasses should be of great help. Many smartphones now have dimming features for the evening. Use them.


Sadly, there is no way we can eliminate artificial blue light from our lives. Our eyes are constantly bombarded by this light that disrupts our natural hormone production and affects our sleep quality. Without proper sleep, we lose cognitive and motoric functions with time, and long-term exposure can even lead to severe diseases like diabetes and cancer. Don't underestimate the effects of blue light on your health, and do what you can to protect yourself, at least during the night.
April 07, 2021