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You're in bed. You actually wanted to sleep. But the phone is still there. Just a quick look. And then an hour has passed and you're more awake than before.
That's not just about the content. It's the light itself.
Your eyes contain special light-sensitive cells – called intrinsically photosensitive retinal ganglion cells (ipRGC). These cells respond especially strongly to short-wavelength blue light and are directly connected to the suprachiasmatic nucleus – the main pacemaker of your internal clock.
When blue light hits these cells, the brain sends a clear signal: it's daytime. Melatonin is suppressed. Cortisol stays active.
This makes evolutionary sense – blue light is the light of the daytime sky. But your phone, your laptop, your TV all emit the same light. Even at midnight.
People with ADHD already have a delayed melatonin release – the internal clock naturally runs behind. Evening blue light shifts this release even further.
Lockley et al. (2003) showed that even brief exposure to short-wavelength light significantly suppresses the melatonin curve. No long laptop evening needed – half an hour is enough.
On top of that: the ADHD brain is more susceptible to dopamine-triggered distraction. Every new image, every new post, every notification triggers a small dopamine hit. The brain wants more. It's not ready to sleep – it's in search mode.
Blue light plus dopamine stimuli plus an already shifted rhythm. That's not a good evening program.
Chang et al. (2015) compared in a controlled study what happens when people read on a tablet before sleep – once with a normal display, once with reduced blue light.
The results: the group with normal blue light fell asleep later, had less REM sleep, and felt less well-rested the next morning – even with the same sleep duration. The suppressed melatonin release shifted by more than an hour.
An hour of worse melatonin curve. Because of a tablet. That's not trivial.
1. Activate blue light filters
Every modern device has a night mode or blue light filter. iOS: "Night Shift." Android: "Eye Comfort" or similar. These filters reduce the blue component of the display and warm the color. Best set to activate automatically from 8 or 9 PM.
Software like f.lux does the same for laptops and automatically adjusts color temperature to the time of day.
2. Blue light glasses for the last hour
Amber-colored blue light blocking glasses block most of the short-wavelength light. Studies show: wearing them 2 to 3 hours before sleep leads to faster sleep onset and better reported sleep quality.
3. Put screens away consistently earlier
Filters help. But they don't solve the dopamine problem. If you actually want to sleep earlier, putting the phone down helps more than any filter. The rule of thumb: 30 to 60 minutes before sleep. Don't look away – put it away.
4. Make the exit easier
The hardest moment isn't sleep – it's stopping. Build yourself an exit mechanism: "after this video, I put it down." Set an alarm as a reminder. Not as a wake-up call, but as a "phone away" signal.
5. Have alternative activities ready
When the phone is away – what then? A book. A podcast without a screen. A sketchbook. Something that doesn't need screens but still keeps your brain slightly occupied while it winds down.
You now know why blue light is bad. That doesn't change anything yet.
The ADHD brain often knows very well what would be good for it. The problem is acting on it. That's why external structures help more here than intentions: automatic filters, an alarm as an exit signal, the phone physically in another room.
Not willpower. Increase friction.
---
Disclaimer: This article is for educational purposes and does not replace medical or therapeutic advice.
- Lockley, S.W., et al. (2003). High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. *Journal of Clinical Endocrinology & Metabolism*, 88(9), 4502–4505. [PubMed](https://pubmed.ncbi.nlm.nih.gov/12893985/)
- Chang, A.M., et al. (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. *PNAS*, 112(4), 1232–1237. [PubMed](https://pubmed.ncbi.nlm.nih.gov/25535358/)
- Bijlenga, D., et al. (2019). The role of sleep timing in adult attention-deficit/hyperactivity disorder. *Sleep Medicine*, 45, 119–127. [PubMed](https://pubmed.ncbi.nlm.nih.gov/30817948/)
Blue Light and Sleep
Your phone is fighting your brain – and usually winning
Just Five More Minutes
You're in bed. You actually wanted to sleep. But the phone is still there. Just a quick look. And then an hour has passed and you're more awake than before.
That's not just about the content. It's the light itself.
What Blue Light Does in the Brain
Your eyes contain special light-sensitive cells – called intrinsically photosensitive retinal ganglion cells (ipRGC). These cells respond especially strongly to short-wavelength blue light and are directly connected to the suprachiasmatic nucleus – the main pacemaker of your internal clock.
When blue light hits these cells, the brain sends a clear signal: it's daytime. Melatonin is suppressed. Cortisol stays active.
This makes evolutionary sense – blue light is the light of the daytime sky. But your phone, your laptop, your TV all emit the same light. Even at midnight.
Why This Hits Twice as Hard with ADHD
People with ADHD already have a delayed melatonin release – the internal clock naturally runs behind. Evening blue light shifts this release even further.
Lockley et al. (2003) showed that even brief exposure to short-wavelength light significantly suppresses the melatonin curve. No long laptop evening needed – half an hour is enough.
On top of that: the ADHD brain is more susceptible to dopamine-triggered distraction. Every new image, every new post, every notification triggers a small dopamine hit. The brain wants more. It's not ready to sleep – it's in search mode.
Blue light plus dopamine stimuli plus an already shifted rhythm. That's not a good evening program.
What Chang et al. Found
Chang et al. (2015) compared in a controlled study what happens when people read on a tablet before sleep – once with a normal display, once with reduced blue light.
The results: the group with normal blue light fell asleep later, had less REM sleep, and felt less well-rested the next morning – even with the same sleep duration. The suppressed melatonin release shifted by more than an hour.
An hour of worse melatonin curve. Because of a tablet. That's not trivial.
What Actually Helps
1. Activate blue light filters
Every modern device has a night mode or blue light filter. iOS: "Night Shift." Android: "Eye Comfort" or similar. These filters reduce the blue component of the display and warm the color. Best set to activate automatically from 8 or 9 PM.
Software like f.lux does the same for laptops and automatically adjusts color temperature to the time of day.
2. Blue light glasses for the last hour
Amber-colored blue light blocking glasses block most of the short-wavelength light. Studies show: wearing them 2 to 3 hours before sleep leads to faster sleep onset and better reported sleep quality.
3. Put screens away consistently earlier
Filters help. But they don't solve the dopamine problem. If you actually want to sleep earlier, putting the phone down helps more than any filter. The rule of thumb: 30 to 60 minutes before sleep. Don't look away – put it away.
4. Make the exit easier
The hardest moment isn't sleep – it's stopping. Build yourself an exit mechanism: "after this video, I put it down." Set an alarm as a reminder. Not as a wake-up call, but as a "phone away" signal.
5. Have alternative activities ready
When the phone is away – what then? A book. A podcast without a screen. A sketchbook. Something that doesn't need screens but still keeps your brain slightly occupied while it winds down.
The Gap Between Knowing and Doing
You now know why blue light is bad. That doesn't change anything yet.
The ADHD brain often knows very well what would be good for it. The problem is acting on it. That's why external structures help more here than intentions: automatic filters, an alarm as an exit signal, the phone physically in another room.
Not willpower. Increase friction.
---
Disclaimer: This article is for educational purposes and does not replace medical or therapeutic advice.
Sources
- Lockley, S.W., et al. (2003). High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. *Journal of Clinical Endocrinology & Metabolism*, 88(9), 4502–4505. [PubMed](https://pubmed.ncbi.nlm.nih.gov/12893985/)
- Chang, A.M., et al. (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. *PNAS*, 112(4), 1232–1237. [PubMed](https://pubmed.ncbi.nlm.nih.gov/25535358/)
- Bijlenga, D., et al. (2019). The role of sleep timing in adult attention-deficit/hyperactivity disorder. *Sleep Medicine*, 45, 119–127. [PubMed](https://pubmed.ncbi.nlm.nih.gov/30817948/)