How Does Blue Light Affect Sleep And Health?

Blue light wreaks havoc on our ability to prepare for sleep in the evening because it blocks melatonin production, a hormone that regulates sleep.

Our bodies are wired to respond to light — the rising sun signals us to start the day, and the setting sun triggers biological processes that prepare us for rest. However, our modern lifestyles often require us to work indoors past sunset.

Artificial lighting and a life accustomed to phone, tablet, and TV screens have kept us awake later and later past sundown, proving there is a biological price to pay for basking in all this light.

We'll break down everything you need to know about blue light and sleep patterns and offer a solution to how you can improve your sleep hygiene and overall health.

The Circadian Rhythm And Light

The circadian rhythm is our body's internal clock that tells us when to sleep, wake, and eat. This biological system is sensitive to environmental cues, such as light and temperature.

Visible light a lot more intricate than meets the eye.

All light comprises of multiple visible and sometimes invisible light rays with a range of effects on the human body.

While our internal clock is calibrated to sunlight, artificial lighting is proving to affect our sleep patterns and overall health, too because of the types of light rays present in artificial lighting.

Sunlight contains red, orange, yellow, green, and blue visible light, and invisible ultraviolet rays (UV).

While our eyes can't detect ultraviolet light rays at a wavelength of 100–400 nm [1]. UV light has short wavelengths that carry a lot of energy, enough to inflict a sunburn on the skin. 

Blue light has a wavelength of between 380 –500 nm, only slightly longer than UV [2], still carrying a lot of energy in these waves.

Some studies are looking at the physiological effects of artificial long-term blue light exposure and the potential damage it has to our circadian rhythm in old age [3].

What Exactly Is Blue Light?

Blue light is virtually everywhere, but sunlight is our main source of blue light exposure.

Our bodies have adapted to become highly responsive to light for two main mechanisms.

  1. Image forming to see color and process environmental information during the day
  2. Non-image-forming adaptations, including our behavior to light — feeling more alert and an uplifted mood [3].


Blue light isn't all bad.

Remember, our bodies are adapted to work alongside sunlight. Blue light is beneficial for us during daylight hours, helping us feel more alert, energized, and attentive.

However, indoor lighting, including LED, fluorescent, and digital devices all emit this blue light spectrum, stimulating us later into the evenings when we should start to feel tired.

Melatonin production, one of the main hormones involved in the sleep-wake cycle, is suppressed while we're exposed to light. Blue light waves result in melatonin suppression 3 times more potent than long-wavelength light (+530 mn) [4].

As a result, our circadian rhythmic patterns become irregular, affecting our ability to get enough sleep at night.

The Health Effects Of Poor Sleep Hygiene

Health experts recommend 7–9 hours of shut-eye each night [5].

Sleep is when our body repairs and regenerates, working to regulate hormone function, rebuild muscle, and strengthen neural pathways to retain memories.

Not prioritizing sleep has negative consequences on our overall health.

More than feeling groggy the next morning, a lack of sleep can lead to poor cognitive function, poor decision making, and slower reaction times, leading to an increase in motor vehicle accidents [6].

The Common Consequences Of Sleep Deprivation:

  • Difficulty concentrating
  • Mood swings
  • Poor memory
  • Weakened immune system
  • Increased propensity for accidents and injury
  • Weight gain
  • High blood pressure
  • Low libido
  • Increased risk of heart disease
  • Depression


3 Tips To Limiting Blue Light Exposure In The Evenings

Our bodies have to come to expect blue light exposure in the day with the cycle of the sun. When we continue our exposure to blue light well into the evenings, it affects our body's cues to wind-down and to prepare for sleep.

If you find you're having a difficult time getting to bed at a reasonable time or you find it takes longer to fall asleep, you may want to consider making these simple changes to your lifestyle to mitigate the effects of blue light on your sleep cycle.

1. Limit Your Screen Use

Blue light emitted from electronic devices can interfere with our ability to fall asleep and stay asleep if we're using them round the clock.

Some people practice a no-screen rule at least one or two hours before bedtime to let their melatonin levels rise, making them feel sleepy.

Most smartphones and computers have a blue light screen filter you can download to block blue light rays if you need to use your device late into the evenings.

These filters only allow red or amber light to appear on the screen, which has the least effect on your body's circadian rhythm and is therefore much more sleep-friendly.

2. Consider Blue Light Blocking Glasses

Blue light blocking eye-wear has become extremely popular among people who work on computers for long hours or are extremely sensitive to the effects of blue light at night.

These glasses may help to reduce eye strain at your desk, and it's best combined with a blue light screen filter on your devices in the evenings. More research needs to be conducted on how effective these glasses block blue light rays.

3. Dim The Lighting In Your Home

Reducing the intensity of your lighting in the evenings may help you stimulate melatonin production, leading to drowsiness at a more appropriate time, so you reach your 7–9 hours of recommended sleep.

If you'd like to take the lighting in your home one-step further to improve your sleep routine, you can move onto the next recommended tip.

4. Opt For KOZE Sleep Bulb 

LED lightbulbs are much more energy-efficient than incandescent and even fluorescent lights. However, LEDs also produce more blue light rays, messing up our sleep cycle.

KOZE Sleep Bulbs are unique LED amber bulbs that you use from sunset to bedtime to help you fall asleep naturally by optimizing melatonin secretion.

The amber light spectrum is significantly less disruptive to the circadian rhythm, allowing you the convenience of a well-lit space without sacrificing your sleep quality.

These bulbs implement technology studied by NASA to regulate astronauts' circadian rhythms in space. KOZE LED bulbs contain zero blue light waves, making them the ideal night light.

KOZE bulbs have an E26 base to fit the most common household light fixtures with a 25,000-hour bulb life — it'll last you a lifetime.

The Takeaway: How Does Blue Light Affect Sleep? 

If you're struggling with getting enough quality sleep each night, your exposure to blue light may be to blame. 

When blue light disrupts our melatonin production, we still feel stimulated well into the night, causing us to miss out on those precious hours of sleep. 

Get back to a healthier sleep cycle by limiting your exposure to blue light in the evenings. KOZE Sleep Bulbs offer an excellent night light solution that helps optimize melatonin production naturally, so you can fall asleep at an appropriate time and stay asleep throughout the night. 

Learn more about KOZE light and other tips to a healthier sleep routine by visiting the blog or signing up for our newsletter.