June 20, 2013
Artificial Light Cutting Melatonin-Driven Sleep

We are staying up too late because our computer monitors, TVs, and room lights are boosting wakefulness by suppressing melatonin.

Before the widespread use of electric light, people probably experienced that second wind in the mid-afternoon, keeping them going until night fell. But light exposure after sunset signals 'daytime' to the SCN, shifting the clock later, postponing the second wind and delaying the onset of melatonin secretion.

LEDs are rich in short wavelength light in the frequency rate that suppresses melatonin production. Lack of sleep boosts appetite. I bet this is a substantial contributor to the rise in obesity.

We are in the midst of a little noticed large scale sleep deficiency.

Today, 30% of all employed US adults and 44% of night workers report averaging less than 6 hours sleep per night1, whereas 50 years ago less than 3% of the US adult population slept so little.

I am just about to try UV-blocking glasses in the evening to see if they'll get me sleepy sooner.

Share |      Randall Parker, 2013 June 20 08:46 PM 

Sam said at June 21, 2013 11:46 PM:

I have very very serious problems sleeping. Funny you should talk about sleep disorders. I just downloaded a program last night called f.lux . It ,"...makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day.

It's even possible that you're staying up too late because of your computer. You could use f.lux because it makes you sleep better, or you could just use it just because it makes your computer look better... "

Going to run it right now. Had forgot about it. Maybe it will help me and others.


Mercer said at June 22, 2013 10:25 AM:

I mentioned this once to my optometrist. He replied that the amount of light from electronics is so tiny compared to sunlight he did not think it would make a difference.

shiva1008 said at June 22, 2013 10:37 AM:

It was originally thought that the human circadian clock was set to 25 hours, but more recently it has been found that this effect was manifesting in the study due to artificial light.


"Accepting the near-24-hour period means that all the ideas about daily human rhythms that we take for granted must be rethought," Czeisler says. For example, biological clock lore states that we drift to a later wake-up hour on weekends because we fail to reset the 25-hour cycle each morning as we go to work.

"We’re not drifting," Czeisler insists. "We’re pushing ourselves to a later time with our exposure to electric lights from sunset to bedtime. That resets our biological clocks."


Although, waking up and staying up later has been found to be strongly correlated with higher IQ, most likely due to novelty-seeking associated with high IQ:


I am definitely one of those people who tends to stay up later when left unfettered. But it turns out that this is due more to being inundated with information and having artificial light, rather than some innate mechanism, which really wouldn't make any sense. It's also hard, when coming home from work, to just have dinner and go to sleep, because then during the week your whole life would be work! Alas...

Sam said at June 22, 2013 8:41 PM:

I think in my case it's genetic. My Mother is exactly the same. Given no need to be anywhere she and I stay up until 4:00 A.M. then get sleepy. My Brother and Father completely different. Both early risers.
Heard a theory one time that certain individuals in a tribe would stay up and watch the camp in the early pre-history days. Most tribal attacks I've read about happen early mornings. Someone watching would be a good survival tool for the tribe. I can be tired at 9:00 PM and at 10:00 start waking up. I can toss and turn all night trying to sleep but can lay on the couch in the evening around 4:00-5:00 PM and go right to sleep. Go figure. The internet has made it worse.
Very weird I know. I wish I wasn't this way sometimes. I do like the night though. Peaceful. I like people but I don't mind being by myself.

On the software f.lux. It makes the screen redder at night. Bluer duing the day.

Bob said at June 30, 2013 4:35 PM:

Randell, I got those orange glasses from Amazon and they work surprisingly well. They do not fit over regular glasses however.

Blue and violet light is bad for eye aging too, just not as bad as UV. I decided to turn my PC monitor's blue level to half of red and green. It looked very strange for the first 10 minutes, now I am used to it and I can't tell the difference. Then I turned it down to 30%, same thing, after a short while it looks normal.

One fun thing about the orange glasses is that when you blink or close your eyes wearing them, instead of the blackish dark red from blood vessels, you see a bright and vivid violet color. This effect disappears after about 5 seconds.

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