How does blue light affect your sleep?

Have you ever found yourself staring at a computer screen for hours, working, studying, browsing or watching a movie? You would stay up until very late, only to find yourself wide awake as soon as your head hits the pillow.

Although there are a few key things that can impact your sleep quality (link to blog), how much time you spend using your wireless devices is one of the major influencers of how well you will sleep.

And it is mainly because of blue light.

What is blue light?

The sunlight we are normally exposed to is made of a few different light rays: red, orange, yellow, green, blue and many shades of each of these colors. (Read more about light in our Beginner’s guide to electromagnetic radiation – link to blog).

It is fair to say that sunlight is the main natural source of blue light, helping us to stay awake and alert during the day.

On the other hand, Fluorescent and LED lighting, flat-screen TV screens, smartphone screens, tablets, computers are man-made devices also emitting blue light.

According to Dr. Heiting, Doctor of Optometry (O.D.), although the amount of  blue light these devices emit is only a fraction of that emitted by the sun, it is the amount of time we spend using them and how close to the screens we are that can have possible long-term effects on our health.

The body’s biological clock: The Circadian Rhythm

Imagine your body has a biological clock running on a 24 hour cycle. This biological clock, called the circadian rhythm or the circadian clock, controls your sleep-wake cycle.

Your eyes help you recognise which part of the sleep-wake cycle it is currently in. They react to the exposure to light, including blue light, through light-sensitive cells.

During night time, the eyes signal to the brain that it is time to sleep and regenerate.

Darkness also causes the body to produce a hormone called ‘melatonin’. This hormone, produced in the pineal gland of our brain, signals the body to prepare for sleep. Beside this, melatonin has antioxidant and anti-inflammatory properties and contributes to a healthy function of the body’s immune and neurological systems.

How does blue light impact on your sleep?

Blue light keeps you more alert and awake and tricks the body into thinking it is still daytime.  The body’s clock is now shifted and out of sync, causing you to have trouble falling asleep, not having a deep enough sleep and waking up tired.

As a result, the body produces very little to no melatonin during night time.

A 2014 study done by researchers at the Harvard Medical School in Boston showed that reading a backlit device before bed makes worsens your sleep significantly more than reading a paper book under dim light.

The study reported that people who used an iPad at night:

  • Produced 55% less melatonin;
  • It took them an extra 10 minutes to fall asleep
  • Had less so called REM (Rapid Eye Movement) sleep during the night, which is when we dream.

On waking up the next day, the iPad readers felt sleepier, and it took them longer to feel alert, compared to the book readers

Interestingly, the next night the iPad readers’ circadian clocks got delayed by more than 90 minutes and their bodies started to feel tired an hour and a half later than normal.

What happens when you don’t sleep?

Not giving your body the vital rest it needs can lead to all sorts of other problems.

Lack of sleep prevents your brain to clear itself out of toxins built up during the waking hours.

A recent study  lead by researchers from the Washington University School of Medicine in St. Louis, MO, suggests that adults who do not get enough deep sleep may be on their way to developing Alzheimer’s disease.

Poor sleep might cause memory issues, trouble with concentration or mood changes. It can also weaken your immune system, increase inflammation and the risk for type 2 diabetes.

Improve your sleep hygiene for better health

It is now clear how important sleep is and why you should reduce your exposure to blue light during night time. Here are 5 tips to get you there:

  1. Use blue light blockers and filters on your devices. It will help you reduce exposure to artificial blue light during the day.
  2. Stop any activity on your mobile devices and computers at least 2-3 hours before going to bed. Allow your body to start preparing for sleep.
  3. Dim the lights during the evening. Switch off any LED lights and choose a softer, orange and yellow light to reduce blue light exposure.
  4. Like reading? Opt in for a book or paper-like e-reader without backlit background.
  5. Switch off wifi and remove your phone and any wireless devices from your bedroom during the night. Wireless devices emit electromagnetic radiation that can also affect your sleep (link to blog – to come)

To find out more about how you can supercharge your sleep, read our blog post titled ‘5 Top Tips to help you sleep like a baby’. (link – blog coming today).



Author Veronika Appleford Divincova

Author Bio:

Research assistant, educator and content creator at Qi-Technologies.

In life, I believe that with more knowledge and understanding we can make better decisions.

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