What Color Light Is Good for Sleep

by sleep wellness

Do you have trouble falling asleep?

Do you wake up in the middle of the night and can’t go back to sleep?

Do you often feel tired during the day?

Is it bad to sleep with a nightlight on?

If the answer is yes, then you might have a love-hate relationship with the lighting in your home. Yes, you read that right. Light in your premises has a huge impact on how well you rest.

In this article, we explore the connection and reveal what the best light color for sleep.


Last updated: 2021

How Light Affects Your Brain and Sleep Cycle

Whether you realize it or not, light plays a crucial role in numerous biological functions.

The circadian clock uses light to determine when your body should be awake or asleep.

This internal process is also responsible for the regulation of hormone levels, metabolism, appetite, body temperature, immune system, and so forth.

Let’s dive into the science behind the circadian rhythm.

The human retina consists of photosensitive (ipRGC) cells that catch any light from the visible spectrum and transmit messages to the suprachiasmatic nucleus (SCN). These photoreceptors respond the most to the low wavelength of blue light (450–485 nm) and are least sensitive to the high wavelength of red light (625–740 nm).

The SCN is located in the hypothalamus and is responsible for how the sleep cycle works. It receives information about the illumination of your body. Then sends it to the pineal gland which releases melatonin – the sleep hormone

Spectral Colors: Wavelength (in nanometers):

Violet 380–450 nm

Blue 450–485 nm

Cyan 485–500 nm

Green 500–565 nm

Yellow 565–590 nm

Orange 590–625 nm

Red 625–740 nm

What it all means

“Simply put, when a healthy amount of red and blue light reaches the SCN during daylight hours, you will experience a good night’s sleep. Also, you will feel more energetic, have a good appetite, and balanced hormone levels.” shares Jonathan Prichard, CEO of Mattress Insider, “On the other hand, if you don’t go outside often enough and you aren’t exposed to natural daylight, you’ll probably have restless sleep, and often feel weary.” he adds.

How Poor Sleep Impacts Your Body

At first, sleep deprivation leads to irritation, unproductiveness, tiredness, bad memory, lack of concentration, mood swings, and more. When sleep disorders turn to chronic, they might cause a wide range of health problems.

Six unwanted consequences of chronic sleep deprivation:

  1. Inflammation: People who sleep for too short or too long have an increased amount of inflammatory markers.
  2. Weight gain: Not enough sleep causes hormonal disbalance. For example, it decreases the amount of Leptin, a hormone responsible for suppressing appetite. Abnormal sleep is also related to Type II diabetes.
  3. Poor cognitive functions: Not enough sleep hurts vigilance and lowers your response times. Particularly, not getting enough sleep can impact cognitive functions connected to emotional data.
  4. Weakened immune system: Poor sleep reduces the strength of your immune system thus making sleep-deprived people prone to viruses.
  5. Risk of heart disease: Sleep disorders increase blood pressure and play a role in heart attacks and other cardio-vascular diseases.
  6. Physical problems: High allergy sensitivity, hair loss, skin issues, and more.

The Dual Side of Blue Light

When you are outside you receive natural sunlight which covers the whole spectrum of light, including blue light. This type of illumination is extremely important for the regulation of your circadian clock.

Modern smart devices also emit blue light harmful to your eyes. You can read more about that in this information-packed Forbes article.

So, when you work late on your computer or scroll through social media on your phone before bedtime, you actually tell your body to be alert, and awake.

If you try to fall asleep right after that, you won’t be able to quickly drift away even if you have the comfiest mattress and pillow.

Pro tip:

Activate night mode on your smartphone and reduce the brightness of the screen when you use it in the evening.

It’s a mistake to turn bright lights on in the middle of the night when you have trouble dozing off. You should not use the background sound from the TV to relax and fall asleep again. All of the artificial blue light has high color temperature and makes your brain think it’s daytime.

Check out the table below to compare the color temperature of various light sources:

Light Source Color Temperature (in Kelvins)
Candles 1900 K
Incandescent light bulbs 2400 – 2700 K
Warm LED or fluorescent lights 2700 – 3000 K
Studio lamps 3200 – 3400 K
Daylight 5000 K
Cool LED or fluorescent lights 5500 – 6000 K
Cloudy sky 6500 K
LCD Screen 6500 – 9500 K
Clear blue sky 10 000+ K

Fun fact:

The aesthetic categorization of colors in warm and cool hues is actually reversed. Blue light has the highest color temperature and red – the lowest.

To ensure you fall asleep easier, avoid using your laptop or smartphone at least half an hour before bedtime. Substitute screen time with a good book, plans for the next day, or a compromise – a meditation app – you can read more here or sounds to help you fall asleep – you can read more here.

Is Red The Best Sleep Color to Induce Sleep?

As we mentioned above, red light has a lower color temperature than natural sunlight.

That’s why it has a reverse effect on the circadian rhythm compared to blue light.

If you are exposed to red light in the evening, your body will release more melatonin and you will naturally drift away.

With red light, it’s quite the contrary. It is one of the natural ways to promote the production of melatonin.

Red light has a handful of other health benefits:

  • Red light helps people experiencing severe migraines by significantly reducing the frequency of headaches.
  • It enhances the cognitive functions of people suffering from traumatic brain injury or post-traumatic stress disorder.
  • Red light therapy is beneficial for inducing sleep among people with serious sleeping illnesses.
  • It improves the quality of sleep after only a few light therapy sessions.
  • It stimulates the release of melatonin and cuts down the time you need to fall asleep.

What About Green Light?

Scientists conclude that blue light suppresses the production of melatonin and thus affects the whole sleep cycle. But what is the case with green light?

Several clinical studies claim that green light has the same effect because it has a similar wavelength to that of blue light.

But one team had a different approach.

Researchers from Oxford University tested how different light affects the sleep cycle of mice. It turned out that it took mice less time to fall asleep when exposed to green light in comparison to blue and violet light (you can see the full sudy here).

However, we should take into consideration the fact that mice are nocturnal animals. So perhaps green is not the best sleep-inducing color for humans.

In other words, if you are exposed to green light before going to bed, you will probably have a hard time falling asleep.

Is It Bad to Sleep with a Nightlight On?

The answer depends on the nightlight color in your bedroom.

It is harmful to sleep with a blue or bright white light. Even if your eyes are closed, the illumination still gets detected through the eyelids. The brain confuses the synthetic light for natural daylight thus significantly decreases the amount of melatonin. In fact, all hormone functions are disrupted and might lead to various health problems.

It is okay to sleep with a red nightlight. As we mentioned above, it induces sleep and assists the circadian rhythm because it has lower color temperature.

Pro tip:

Place a red light in your bathroom or hallway if you often get up in the middle of the night.

This won’t affect your sleep cycle as much as the regular light will.

What Light to Wake up to?

Nighlight should have color temperature similar to sunset shades, it’s only logical that the light for waking up is the one that resembles sunrise.

In the summer, the sun is your natural alarm clock. When the rays enter your bedroom the circadian rhythm detects it’s time to wake up your body. But when it’s winter and the weather outside is gloomy, your biological clock needs external assistance.

A good idea is to invest in a bedside lamp that starts glowing half an hour before the time you need to wake up. Its light gradually changes from orange to white thus allowing you to gracefully exit the sleep cycle.

You will feel refreshed in the morning and you won’t hit the snooze button as many times as before.

Expert opinion of an experienced electrician

According to Jordan Vellutini, managing director of Westline Electricians Company, it’s a good idea to switch the lightbulb in your bedroom, bathroom or hallway with one emitting red light. You can also opt for smart LED lights.

With a few clicks on your phone or tablet, you’ll be able to adjust the illumination in your home from bright white to red.


Sleep deprivation can cause multiple health issues in the long run but regular exposure to red light can prevent that. This type of light improves your circadian rhythm and the secretion of melatonin.

You will fall asleep faster and will feel better rested in the morning.


  • Bob Ozment

    Bob has been testing and writing about all things sleep (and especially blankets, air mattresses and folding beds), for 8+ years now. before that, he worked as a Quality Assurance Manager with one of the bigger names in the sleep industry. He holds a masters degree Statistics, Actuarial & Data Sciences from the central Michigan University at Mount Pleasant. He's one of the people who designs our producing testing and statistical models. He’s a stomach sleeper, but nobody’s perfect.