What are the Effects of Blue Light on Sleep?

What are the Effects of Blue Light on Sleep?
Blue light is the light of wakefulness. Blue wavelengths most intensely affect your sleep-wake internal clock. There is a reason why doctors ask you to keep your smartphones and other electronic devices away before bedtime. The screens of electronic devices like smartphones, tablets, computers, and TVs emit blue light that disrupts our natural sleep cycle.

Using electronic devices within an hour of hitting the bed leads to unsatisfied sleep. By decreasing exposure to bright light after sunset, in general, and blue light in particular, is a smart way to signal your body that sleep is just around the corner and you will be getting ready for bed soon.

What is Blue Light?

Blue light forms the part of the visible light spectrum. One-third of all visible light is classified as blue light. The source of this light is obviously sun but blue light also comes from digital screens and LED lights.

It is quite likely that you are reading this article on a device that emits blue light. How many hours do we spend on a digital screen every day? Should we be concerned about the amount of blue light hitting our eyes?

Light is made up of electromagnetic energy, which is not visible to the naked eye. Our eyes perceive colors of light based on the amount of energy they contain. These energies travel around us and even through us in waves.

As mentioned above, blue light is the portion of the visible light spectrum. It affects alertness, sleep-wake cycles, and hormone production.

How Does Blue Light Affect Sleep?

Natural blue light, which we get during the day, makes us alert, active, and energized. However, when you see the same light from electronic devices in the evening, your brain is fooled into thinking that it’s daytime. When this happens, your body stops producing melatonin – sleep hormone. Melatonin is nature’s signal to our body that it is time to sleep.

Our body starts creating melatonin a few hours before sleep. Darkness is a melatonin trigger, but this light hinders its production.

This is bad for us, but you know what’s worse? Teens are more susceptible to the adversities of blue light than adults. It is quite likely for you to toss and turn past your normal bedtime. And by adding other sleep obstructions like the sleep-wake internal body clock that lets one stay awake, homework and distractions, and early school start times owing to daylight saving. All the aforementioned conditions are a perfect recipe for sleep deprivation. Blue light created by smartphones has an adverse impact on sleep, especially if you use your electronic devices before bedtime.

Sleep is important for our overall well-being. Proper sleep helps our heart and blood vessels stay in check. A sleep-deprived person, for whatever reason, is prone to insomnia. Insomnia is when you regularly have trouble falling asleep, staying asleep, or getting good quality sleep, even when you have the chance to do so.

It’s more than just a few nights of restless sleep; it’s a chronic issue that can really affect your daily life, making you feel tired, grumpy, and less able to focus.

One surprising culprit behind insomnia is light. Our bodies have a natural sleep-wake cycle called the circadian rhythm, which is heavily influenced by light. In the evening, as it gets darker, our bodies start producing melatonin, a hormone that makes us feel sleepy. But exposure to bright lights, especially blue light from screens like phones, tablets, and computers, can mess with this process. It tricks our brains into thinking it’s still daytime, delaying melatonin production and making it harder to fall asleep.

So, staying glued to screens before bed can lead to tossing and turning instead of drifting off into a peaceful slumber.

What are Blue Light Sources?

Every day, Americans spend around 7 hours on electronic devices. That’s a lot of time to stare at this light. Conversely, nine out of ten Americans admit to reaching out for their digital device a couple of times each week before going to bed. It might be an open invitation to insomnia.

Even though the light from your device may appear white. But they emit wavelengths in the range of 400 to 490 nanometers, that’s blue light.

Indoor or artificial sources of blue light:

  • Smartphones
  • TV
  • Tablets
  • Laptop/Computer monitors
  • Gaming consoles
  • Fluorescent light bulbs
  • LED bulbs

What are the health benefits of blue light?

You must be wondering are there any health benefits of this light? Well, yes. It enhances alertness, helps in brain and memory function, and elevates mood. This is what regulates your circadian rhythm – body’s wake and sleep cycle. There are numerous benefits of sunlight. It significantly aids in the growth and development of children’s eyes and sight.

How Does Blue Light Affect Circadian Rhythms?

Circadian rhythms are the biological cycles of our body that have around 24-hour periods. At night, this light can throw your circadian rhythm (biological clock/cycle) off the track. Study shows that not only does your sleep suffer, but this light may lead to cancer, diabetes, heart problems, and weight gain.

Verily, natural light aligns circadian rhythm. Human history is a witness to the fact that our biological clock was closely aligned with sunrise and sunset. However, the advent of artificial light got the clock confused and our circadian paid heavily for it.

We are exposed to different kinds of light before we hit the bed, but blue light has the biggest impact on sleep.

During the day, blue light from the sun makes us feel energized, alert, productive, and proactive. This light stimulates the part of our brain that makes our brain function. The improved performance of our body during the day due to the same light tunes our circadian rhythms and prepares us for better sleep at night.

Circadian rhythm disorder occurs when your body’s sleep-wake cycle is not properly aligned with the environment.

Ways to Manage Blue Light

The best way to reduce exposure to it is by turning off its sources. You can do this by dimming or reducing LED or fluorescent light in your space. Also, switch off electronic devices after dark.

Blue light glasses also help with eye strain. They reduce the direct impact of this light on your eyes. However, these glasses do not work on everyone. Blue light-blocking or amber glasses work by reducing the melatonin-suppressing effects of light.

For practical reasons, you cannot turn off all blue light sources after dark. However, you can reduce exposure to it in a variety of ways. This will prevent it from affecting your sleep in a negative manner.

  • Make it a habit: Set an alarm to remind yourself to turn off electronics two to three hours before bedtime.
  • Switch your lamp: If you like reading in bed, use a lamp that emits red or orange light instead of blue.
  • Learn to dim: Reduce the brightness of your electronic screens or use the “night mode” feature available on some devices.
  • Use an app: If you need to use devices before bed, try a smartphone or computer application that reduces its emission.
  • Enhance your sleep environment: If you can’t dim or turn off all light sources inside your bedroom, use an eye mask to block them once you hit the bed.


The information provided in this article is intended for general informational purposes only and should not be construed as medical advice. Visit a qualified healthcare professional before implementing any changes to your sleep habits or routines. The tips and recommendations offered here are based on general best practices and may not be suitable for everyone. Individual needs and responses to light exposure and sleep hygiene can vary. Using apps or devices mentioned in this article is at your discretion and responsibility. Our editorial team does not endorse any specific products or brands.