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submitted 23 hours ago by alyaza@beehaw.org to c/technology@beehaw.org

The public freakout about blue light started with a study in 2014. Half of the 12 participants read on an iPad before bed. The rest read physical books. The iPad users took longer to fall asleep, felt groggier the next day and produced less melatonin. The researchers said the culprit was the glow emitted from the iPad's LED screen, which produces a disproportionate amount of light in the upper, bluer end of the spectrum. Under specific circumstances, blue-enriched light disrupts the daily circadian rhythm – our body's natural pacemaker – that uses daylight to help determine when we start to feel tired. Subsequent research seemed to support the findings. Sounds simple, right? It's not.

"This was an incredibly deceptive piece of work," says Jamie Zeitzer, a professor of psychiatry and behavioural sciences at Stanford University, who studies the effect of light on the circadian system. The science wasn't bad, he says, the problem is it brought people to bad conclusions.


After years warnings and millions of people flipping on the blue light filters built into their phones, the latest science suggests screens are not the main culprit here after all. For example, a recent review of 11 different studies and found that the light from screens only delayed sleep by about nine minutes, at worst. Not zero, but not life altering, either.

The amount of blue light emitted by the screens of phones, laptops and tablets has also been shown to be tiny compared to the blue light we receive from the Sun – 24 hours-worth of blue light from digital devices totted up to less than one minute spent outdoors, according to one study. Other studies have shown it's not enough to affect levels of the hormones that control our sleep.

So why am I so tired all the time? Zeitzer and others told me there are lots of other ways that light, blue and otherwise, could be ruining my bedtime. If I really wanted to tackle the blue monster, it was going to take a serious lifestyle change.

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[-] leriotdelac@lemmy.zip 1 points 23 hours ago

I actually feel terrible the following morning of I fall asleep after doing stuff on my phone (which is most of the nights). If not because of the blue light, then why?

[-] Jiggle_Physics@piefed.zip 12 points 21 hours ago

The things you are exposing yourself to on your phone?

[-] leriotdelac@lemmy.zip 1 points 6 hours ago

I'm reading fiction books from screen in the evening, nothing too exciting to disturb sleep, and not too long, so I really doubt it's the reason.

[-] lattrommi@lemmy.ml 1 points 19 hours ago

The electromagnetic field being generated by your phone pinging the nearest cell tower 30 times a second.

[-] Onomatopoeia@lemmy.cafe 0 points 20 hours ago

Well it's clearly not "blue light".

We don't know what you're doing on your phone, so you can't expect us to diagnose your issues.

I can use my phone right before bed with no problems. It has zero affect on me. But I'm not cruising Lemmy or reading crap that gets to me.

[-] leriotdelac@lemmy.zip 1 points 6 hours ago

Ah, I don't ask for any diagnosis from random commenters - if my message left such impression, it was unintentional. My intention was to share my experience and voice out my confusion.

I'll try to clarify because I feel condescending tone in yours and others' comments.

Eye strain / muscle strain or something might still be responsible for the bad feeling the next day. Alternatively, light per se might still be the issue, since I'm one of the suckers with light sensitivity and migraines.

I usually read a book from my screen, and I never do it for too long, unless it's a vacation. I found the article interesting because I blamed the blue light and use filters, but now most probably I would need to search for another solution - or another bedtime activity.

this post was submitted on 10 Apr 2026
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