How does blue light exposure before bed affect sleep quality? Do blue light filters help improve sleep? Does prolonged poor sleep quality lead to negative habits over time?

For my experiment I used research from a public experiment and I also did my own.

Public experiment research.

Public Experiment Design:

• Participants: 13 young men (ages 20-23)

• Conditions:

  1. Blue Light Exposure – One hour of blue light before bed

  2. Incandescent Light Exposure – One hour of warm light before bed

• Measurements:

  • Subjective sleep quality (self-reported)

  • Next-day attention & work efficiency

Original Experiment Design (Before Adjustments):

• Three nights under different conditions:

  1. No blue light exposure before bed.

  2. Blue light exposure from a computer before bed.

  3. Blue light exposure with a blue light filter applied.

• Reaction time tests were used to measure morning alertness and fatigue levels.

• Bedtime (11 PM - 11 AM) and environment were kept consistent.

Personal Experiment.

To experiment my theory, I put myself to the test of  going 3 nights under different blue light conditions. 

1. Zero blue light by not using the computer a while before bed.
2. Another night using it right before bed,
3.  And one more using it with the blue light filter that is built into my monitor on the highest level.

I will test in the morning after of each experiment my reaction time and write down how I feel in my log book and into my presentation and information.

What I did was i put myself under these conditions for 3 nights. Once with a filter, once with no filter and once with no devices an hour before bed. I kept all the times healthy and the same 11PM to 11AM trying not to wake up any earlier or any later than necessary. As I am not a fully grown adult the maximum recommended hours of sleep is 12. The 2 things that will be tested as soon as I wake up will be my reaction time and I will be talking about the effects and how I feel waking up. For the 3 days I went to bed at the exact same time and for all 3 days, I watched the exact same movie on the same computer but on the day with no computer, I watched the movie earlier in the day. 

What Is Blue light?

Blue light is a type of light that has a short wavelength between 400-500 nanometers, Light comes in many different colors, and each color has a different wavelength. Wavelength is like the measurement of the light waves and determines what color we see.  It is measured in nanometers which are very tiny. The shorter the nanometer, the closer it is to the blue slide of the colour spectrum while the higher nanometers are closer to the red side of the colour spectrum. So the size of the wavelength is the colour that your eye can see.

What is Melatonin?

Melatonin is a hormone that controls our sleep wake cycle, also called the circadian rhythm. It's like a signal for the body telling it that it needs to sleep, for example when we get hungry our body becomes agitated and lets us know that we need to go eat something. In this case, melatonin is what makes you feel tired, letting you know to go to sleep. Melatonin is produced in the part of the brain known as the pineal gland. Melatonin is released a little bit in the bloodstream throughout the day but rapidly increases as it gets darker. Blue light tricks your brain into thinking it is daytime when it really is night time keeping you up longer then you should be, stopping melatonin release into your bloodstream, making it harder to sleep. And doing this constantly every single night could make your sleep quality way worse than say it was a week ago. This is why doctors say to avoid screens right before bed as they disrupt your natural melatonin cycle.

What is a blue light filter? What does it do?

A blue light filter alters the colours on your device so the wavelengths of light bigger creating a darker red colour on your screen, most new devices have it but the most common are iphones and newer monitors, you could even purchase blue light blocking glasses! You can set the intensity levels on your device to see how much blue light you want to block out. The higher intensity, the morte red your screen gets. Even just a light intensity filter can do alot but in this experiment, we did the max intensity my monitor had to offer. The higher the intensity also means the more melatonin your body produces.

Hypothesis?

If people are exposed to blue light from electronic devices before they sleep, their sleep quality will decrease because blue light disrupts the production of melatonin, the sleep hormone. If people use a blue light filter, it will significantly increase their sleep quality, but a person who cuts all lights a few hours before bed will have maximum sleep quality if all are under the same circumstances. 

When we look at the data in the first graph, it shows that my reaction time was not much worse then having no computer before bed at all, but when we go to the data of how I felt, I didn't feel that well in the morning and I was more tired than normal days. So using no phone is way better than using it but that doesn't mean the filter is necessarily a bad thing. Using one in moderation could allow you to relax and wind down after long days during your week (but just make sure to not use it for long periods of time and moderately throughout the week).

• Public Study Findings:

  • Participants exposed to blue light reported lower sleep quality than those exposed to incandescent light.

  • Reduced melatonin levels led to longer sleep onset time and lower morning alertness in the blue light group.

  • Work efficiency and attention were also negatively affected.

• Avoiding blue light before bedtime leads to the best sleep quality.

• Blue light filters help but are not as effective as completely avoiding screen exposure.

• Exposure to blue light negatively impacts reaction time and morning fatigue.

• Blue light should be used in moderation at night to balance relaxation and melatonin production.

• The findings from the public experiment align with the hypothesis, reinforcing the conclusion that blue light affects sleep quality.

In conclusion, not using my phone right before bed gave me the best results possible. But the filter gave me similar results but an easier time falling asleep because melatonin was being produced and I was entertained at the same time. Using my computer with no filter gave me bad results not only a bad feeling after waking up but a horrible reaction time because of how tired I actually was. But what is really better though? No phone or a filter? 

When we look at the data in the first graph, it shows that my reaction time was not much worse then having no computer before bed at all, but when we go to the data of how I felt, I didn't feel that well in the morning and I was more tired than normal days. So using no phone is way better than using it but that doesn't mean the filter is necessarily a bad thing. Using one in moderation could allow you to relax and wind down after long days during your week (but just make sure to not use it for long periods of time and moderately throughout the week).

https://humanbenchmark.com/tests/reactiontime

https://www.sleepfoundation.org/bedroom-environment/blue-light

https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side

https://www.youtube.com/watch?v=Ip2GeN4ZSu0&ab_channel=BrainFacts.org

https://www.youtube.com/watch?v=wGnRcX53XBQ&t=37s&ab_channel=DoctorMike

https://link.springer.com/article/10.1007/s41782-024-00276-5#citeas

Uchiumi, T., Ishizawa, M., Takahata, M. et al. The Effects of Pre-bedtime Blue-Light Exposure on Subjective Sleep Quality, Attention, and Work Efficiency in Men Students: A Pilot Study. Sleep Vigilance 8, 215–221 (2024). https://doi.org/10.1007/s41782-024-00276-5

Harvard Health. (2024, July 24). Blue light has a dark side. https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side

Sleep Foundation. (2024, January 12). Blue Light: What it is and how it affects sleep. https://www.sleepfoundation.org/bedroom-environment/blue-light

Human Benchmark. (n.d.). https://humanbenchmark.com/tests/reactiontime

I would like to acknowledge myself for taking part in my own experiment

I acknowledge my teachers at my school for taking a look over my project and being able to take time out of there day to make sure it is good. They gave good feedback and very great and important constructive criticism.