I am always on the lookout for ways to improve myself. Avoiding smartphone use and blue light exposure before going to sleep has been on my radar for quite some time. However, I haven’t been able to commit to it. Until now, I haven’t really reflected on why this is the case. In other words, I had not given it much thought. This blog post is my reflection on this issue. First, I want to explore the benefits of cutting down on smartphone use before bedtime.
Table of Contents
Physiological basis for poor sleep after blue light exposure.
Our eyes contain intrinsically photosensitive retinal ganglion cells (ipRGCs), which represent only a fraction of all ganglion cells (approximately 1-2%) but play a crucial role in regulating sleep. These cells contain a photopigment called melanopsin, a photopigment with peak sensitivity to blue light wavelengths (460-480 nm). These receptors don’t contribute much to what we see, but they act as environment irradiance detectors that monitor light levels.
These ipRGCs project directly to the suprachiasmatic nucleus (SCN) in the hypothalamus, which acts as the body’s circadian clock. When we look at screens right before we sleep, our SCN gets false signals from ipRGCs indicating it’s still daytime, creating confusion in our body’s natural circadian rhythm.
A study indicated that a 2-hour exposure to blue light before sleep has reduced the melatonin level significantly compared to participants without exposure1. A Harvard study has shown that blue light suppressed melatonin for about twice as long as the green light. It shifted the circadian rhythm by twice as much.2
What are the effects on our physiology and body?
- Delayed sleep onset.
- Reduced sleep duration and quality. A norwegian study found that 1 hour of screen time at bedtime resulted in 24 fewer minutes of sleep and a 59% higher risk of insomnia.3
- Disruption of sleep architecture, particularly effecting deep and REM stages of sleep.
- Circadian rhythm shifting – a phenomenon called phase delay.
- Broader responses such as hormone dysregulation, metabolic consequences, and increased stress response.
Reflections on my habit.
I have had this habit for a while now. I have tried to cut down on this, but I have been unsuccessful. I have never really reflected on the reasons behind it. Now, as I think about it, a few reasons come to my mind.
- It has become a habit for me, and breaking habits is difficult.
- What I do is not productive, more often than not, I find myself scrolling through reels and x feed (which has become a racist cesspool)
- At that point in the day, my energy is low. I don’t feel like doing productive things like reading a book or studying. So I end up lounging and mindlessly scrolling through social media.
Actions to break from this habit.
- Try to include a non-visual activity before bed, such as listening to a podcast, audiobook, or just music. I think this is something doable.
- Make use of Apple’s sleep features by turning on Night Mode. I have an Apple Watch, so I plan to check if cutting down on blue light produces tangible results, such as improvements in sleep architecture and duration.
- Journal the subjective feelings you encounter upon waking the next day. Make sure to acknowledge the feelings of being productive and congratulate yourself on a job well done.
- Set a time-out period of 2-3 hours before sleep during which blue light exposure should be reduced. However, keep in mind that this rigid timeframe has not worked well for me in the past.
I need to incorporate these things into my life and see if I can break away from the habit. Paying attention to how and why I feel in a specific way is important to break away from this habit.
- https://www.tandfonline.com/doi/full/10.1080/07420528.2018.1527773#d1e333 ↩︎
- https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side ↩︎
- https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2025.1548273/full ↩︎
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