The Impact of Blue Light on Sleep Patterns: How Screen Time Affects Your Circadian Rhythm

The Impact of Blue Light on Sleep Patterns: How Screen Time Affects Your Circadian Rhythm

In the current age of artificial lighting and lengthy screen time, blue light often gets a bad rep. But actually, the largest source of blue light is the sun. It’s essential to regulating your body’s daily cycles and boosting brain function. 

So why is blue light bad for sleep?

Before phone screens and fluorescent lighting, people woke and slept with the rising and setting of the sun. Now that you have access to blue light 24/7, your body wants to stay awake even when it’s time to rest. 

Read on to discover the connection between blue light and sleep and learn what you can do to avoid harmful blue light and heal your natural sleep cycle

Unveiling the Impact of Blue Light on Sleep Patterns

Blue light and your body have a complex relationship. Blue light helps keep you alert, which is essential for completing daily activities. But it will keep you awake, even when you don’t want to be. 

So how does blue light affect sleep? It depends on when you’re exposed to it. 

Blue light heavily influences your body’s circadian rhythm, which is the “internal clock” that keeps your sleep cycle on track. Blue light exposure during the day gives you fuel, but exposure before bed can derail this important yet delicate system. 

The Basics of Circadian Rhythm

Understanding Your Body's Internal Clock

Whether you find yourself naturally waking up at 7 AM every morning, or you need to set four alarms just to make it to work on time, everyone has an internal clock that regulates their sleep

This clock, otherwise known as a circadian rhythm, is an essential regulatory function. It’s roughly synced to the rising and setting of the sun, so your body knows when to wake and when to sleep.  

Your circadian rhythm doesn’t just affect your sleep quality, though; among other things, it also controls your:

  • Digestive system
  • Hormone regulation 
  • Body temperature

All these systems work together to keep your body in a state of homeostasis, or balance. It tells you everything from when to be hungry, and when to be most active. So if your circadian rhythm is disrupted, it doesn’t just disrupt your sleep, it throws your entire body off balance. 

The Science Behind Circadian Rhythm Disruption

In an ideal world, your circadian rhythm would be perfectly synced with the natural 24-hour light and dark cycle. While nothing is ever perfect, there are certain factors that disproportionately disrupt your circadian rhythm, such as:

  • Night shift hours or inconsistent work hours
  • Jet lag from traveling 
  • Caffeine or alcohol consumption before bed

However, no disruption is more common than blue light exposure before bed. 

Here’s how blue light and sleep work: Sunlight, which is blue light, is only meant to be seen during the day. But now, because of artificial blue light, you can be exposed to “sunlight” at any time. Blue light exposure at night tricks the body into believing it should be awake, hijacking your natural circadian rhythm. 

Blue Light and Its Sources

Shedding Light on Blue Light

Blue light makes up a third of all visible light. 

While many people mainly associate blue light with screen, digital eye strain, and artificial light, the majority of blue light occurs naturally, as sunlight. Blue light emits very short, high-energy wavelengths that are difficult for your eyes to block out.

While blue light from the sun isn’t an issue, artificial blue light from devices can be. 

Devices Emitting Blue Light

While the sun is still the largest source of blue light, there are many artificial sources that are becoming more accessible, and even unavoidable. 

The most common sources of artificial blue light and digital eye strain include:

  • Fluorescent and LED lights
  • TV screens
  • Laptop and computer screens
  • Smartphone and tablet screens

More interior lighting is now being replaced with fluorescent and LED lights. Office buildings, apartments, and even car headlights are overwhelmingly illuminated by blue light, making it increasingly difficult to avoid. 

And odds are, whether it’s for work or play, you use at least one type of blue light-emitting device. The percentage of Americans who use their devices before bed is a whopping 90%.

How Blue Light Disrupts Sleep

Blue Light and Melatonin Suppression

Melatonin is one of the hormones that maintains your circadian rhythm. Your body produces it at night, making you feel sleepy. And what signals your body to produce melatonin? Dim light. 

Blue light exposure before bed suppresses the secretion of melatonin, keeping you wide awake, and making it difficult to fall asleep and stay asleep.

Circadian Rhythm Confusion

Much like jet lag or working the night shift, prolonged blue light exposure disrupts your body’s ability to distinguish day from night.

With jet lag, there is a disconnect between your internal clock and the natural light/dark cycle of the area where you’re staying. Your body may say it’s nighttime, but the beating sun says otherwise. After a few days, your body adjusts to the new time zone. But with prolonged blue light exposure, your body is no longer able to regulate itself. 

Practical Tips for Mitigating Blue Light Impact

Night Mode and Screen Filters

In this day and age, it’s nearly impossible to avoid all screens. Many people need to use a computer for their work, and smartphones are often the main way to communicate with loved ones. Luckily, there are steps you can take to mitigate the blue light you take in from your screens. 

Many computers, phones, and tablets now have settings in place that can limit blue light emission. These “night modes” can tint your screen a warmer shade and de-intensify the light it emits. 

There are also external filters that adhere to your screen, much like a screen protector. These filters block blue light wavelengths from reaching your eyes, neutralizing the light’s negative effects. 

Establishing a Screen Time Cut-off

Not all experts agree on a universal screen time limit, but most recommend a screen time cut-off, typically two to three hours before you plan to go to bed. 

Cutting out nightly screen time is easier said than done. Many people wind down for bed by scrolling on social media or watching TV. Instead of cutting yourself off cold turkey, try to slowly cut back over a few days or weeks, if necessary.

Creating a Sleep-Friendly Environment

Dim Lighting and Sleep Hygiene

It’s important to eliminate as much light as possible from your bedroom for better sleep quality. Even lamps and overhead lights can suppress melatonin production and interrupt your sleep schedule. Consider replacing lamps and nightlights with dim, red lights that won’t influence you as much as blue light. 

Other things you can do to create a healthy sleep environment include:

  • Eliminate distracting sounds
  • Use a comfortable mattress
  • Follow a consistent bedtime routine

Good sleep hygiene works in tandem with blue light avoidance—the more consistently you practice it, the better your sleep will be. 

Alternatives to Screen Time Before Bed

The best way to cut off your screen time is to replace it with more positive habits. 

There are many activities you can do before bed that won’t keep you up all night. You can try to:

  • Read a physical book, or use an e-reader with a display that simulates real paper
  • Take a warm bath
  • Listen to calming music or an audiobook
  • Meditate or write in a journal

Establishing new habits isn’t always easy, but it can make for a smoother transition to cutting out screen time before bed.

The Future of Sleep Tech: Blue Light Solutions

Innovations in Sleep-Friendly Technology

Blue light counteracting technology is steadily finding its way into the mainstream:

  • Blue light glasses – These special glasses allow you to stare at a screen without keeping you up all night. They filter out the blue light wavelengths your eyes can’t filter on their own. You can add blue light blocking technology to your prescription glasses, or get glasses exclusively for blocking blue light.
  • Human-centric LED lights – These lights change in color and intensity throughout the day to mimic natural sunlight and sync with your circadian rhythm. They emit bright blue light in the morning to boost energy and mood, then gradually shift to warmer, lower light in the evening to help you wind down for bed.

As more is discovered about the negative effects of blue light on sleep, expect to see new technologies like this become even more common and accessible. 

Navigating the Blue-Lit Path to Better Sleep

By incorporating these tips into your everyday life, you’ll begin to heal your natural circadian rhythm and achieve better and more restful sleep. 

Blue light isn’t the only factor impacting your sleep. Stress and anxiety can disrupt your natural cycle, causing insomnia and other sleep disorders. Apollo Neuro has developed a wearable device that emits relaxing vibrations to promote better sleep. Users have reported getting an extra thirty minutes of sleep each night, which makes a world of a difference for those struggling at night. 

To find out if an Apollo wearable is right for your journey to better sleep, learn about the science behind Apollo. And to understand more about what’s preventing you from getting good sleep, check out Why Can't I Sleep At Night? 4 Reasons and Ways to Get Back on Track.


UC Davis Health. How blue light affects your eyes, sleep, and health. 

National Sleep Foundation. Understanding Circadian Rhythms. 

Sutter Health. Screens and Your Sleep: The Impact of Nighttime Use. 

Harvard Health. Blue light has a dark side.