Blue light makes the brain think it's time to wake up, just as you're getting ready for bed.
By Olga Khazan
The answer to the question "How'd you sleep?" has, for most
of human history, been "not too well." Even before the advent of
electric light, people slept two or three to a bed, next to a chamber
pot, and with a warmth-giving-yet-high-maintenance fire threatening to
burn out a few yards away.
As Jon Mooallem put it in the New York Times magazine a few years ago, "In
1750, one writer described London between the hours of 1 a.m. and 2
a.m. as a ghastly encampment of 'sick and lame people meditating and
languishing on their several disorders, and praying for daylight.'
So the idea that smartphones and other electronic devices have
interrupted centuries of blissful slumber is somewhat flawed. But to the
extent that we rely on technology to make life better, one domain where
it might be making things worse is, in fact, in the realm of sleep.
Smartphones do seem to be having an impact on how well we snooze, and
this effect seems to be especially severe among young people. A 2012
Time/Qualcomm poll conducted with 4,700 respondents in seven countries,
including the U.S., found that younger people were more likely to say
that they don't "sleep as well because I am connected to technology all
the time": Percent Who Don't Sleep as Well Because of Technology
Percent
of respondents, by age bracket, who said they agreed with the statement
"I don't sleep as well as I used to because I am connected to
technology all the time" at a level of 8, 9, or 10, with 10 points
meaning it describes them exactly (Time/Qualcomm)
This might be because young people are likelier to keep their phones within reach when they are trying to sleep: Where Do You Keep Your Phone While You Sleep?
Time/Qualcomm
Smartphones
and tablets disrupt sleep, in part, because they emit what's known as
"blue" light. This light is picked up by special cells behind our
eyeballs, and it communicates to the brain that it's morning. (Red
light, meanwhile, signals that it's time to go to sleep).
This video from Everyday Chemistry has a good explanation of how that works:
All of this blue light suppresses melatonin,
a hormone that helps with sleep timing and circadian rhythms. At night,
our melatonin levels are supposed to rise in anticipation of sleep. In 2013,
scientists at Rensselaer Polytechnic Institute asked 13 people to use
electronic tablets for two hours before bed. They found that those who
used the tablets while wearing orange goggles, which filter blue light,
had higher levels of melatonin than those who either used the tablets
without goggles on or, as a control, with blue-light goggles on. Melatonin Levels After Two Hours
RPI
The harm caused by blue light has been replicated over and over. In another study, a group of Harvard researchers compared the effect
of 6.5 hours of exposure to blue light, compared to similarly bright
green light. The blue light suppressed melatonin for twice as long, and
it shifted sleep schedules by three hours, compared to an hour and a
half.
Even e-readers, such as the Kindle, can mess with the body's sleep systems. A study published in the Proceedings of the National Academy of Sciences
last year found that e-readers not only suppressed melatonin, they
reduced the total number of REM sleep minutes that participants got. REM
sleep is considered the most restorative form of sleep. REM Sleep with Print Versus E-Book
PNAS
More recently, a study of Massachusetts fourth and seventh graders published in Pediatrics
found that children who slept near a small screen and who had more
screen time "were more likely to have perceived insufficient rest or
sleep in the past week." Not only might the kids have been tempted to
grab their phones in the wee hours and re-commence their game-playing
and snap-chatting, but their devices might have been sounding with
alerts throughout the night. The effects were more pronounced among
Hispanic and African American children than among white kids: Changes in Sleep and Bedtime in the Presence of Screens
Pediatrics
"The irony of blue as an environmental agent is that before the industrial age, it was merely a color," wrote David Holzman
in a paper on the harms of blue light recently. Eighteenth-century
children may have had livestock mewling nearby as they slept, as Mooallem wrote, but at least they didn't have to contend with the scourge of blue light.
Article from The Atlantic online
The elements of a changing world, from technology and business to politics and culture. Read More
“Well, you’re just special. You’re American,” remarked
my colleague, smirking from across the coffee table. My other Finnish
coworkers, from the school in Helsinki where I teach, nodded in
agreement. They had just finished critiquing one of my habits, and they
could see that I was on the defensive.
I threw my hands up and snapped, “You’re accusing me of being too friendly? Is that really such a bad thing?”
“Well, when I greet a colleague, I keep track,” she retorted,
“so I don’t greet them again during the day!” Another chimed in, “That’s
the same for me, too!”
Unbelievable, I thought. According to them, I’m too generous with my hellos.
When I told them I would do my best to greet them just once
every day, they told me not to change my ways. They said they understood
me. But the thing is, now that I’ve viewed myself from their
perspective, I’m not sure I want to remain the same. Change isn’t a bad
thing. And since moving to Finland two years ago, I’ve kicked a few bad
American habits. 1. I don’t fear awkward silences.
I have yet to meet an American who doesn’t dread the awkward
silence. A lull in any conversation is to be avoided at all costs—even
if it means talking about the latest viral cat video or celebrity
breakup.
The Finns I’ve met, on the other hand, embrace the awkward silence.They
understand that it’s a part of the natural rhythm of human interaction.
Sure, Finns know how to have conversations, but they’re not driven by a
compulsion to fill time and space with needless chatter.
On a recent school day, as I dug into a lunch of fish sticks
and steamed potatoes at the teachers’ table in the cafeteria, I was
joined by a Finnish colleague. We exchanged hellos (since, you know, we
hadn’t yet greeted each other that day), and then ate our meals in
complete silence. We had been teaching all morning, and those fleeting
moments of quiet were like a rest for our souls. After 10 minutes, I
glanced up at the clock and, seeing that my next lesson was about to
begin, broke the calm by saying goodbye. Even though we had just given
each other “the silent treatment,” no harm was done. Quite the opposite,
actually. I pushed in my chair feeling refreshed.
On the morning commute to my toddler’s daycare, the subway is
often so packed that we can’t find a spot to sit. And yet it’s
remarkably quiet. On the rare occasions when someone speaks—whether to
bid farewell to a friend or make a quick phone call—my son Misaiel asks
me, “Why they talkin’, Dada?” He is just two years old, but he already
understands the culture of comfortable silence here.
2. I don’t say things I don’t mean.
Before we moved to Finland, my Finnish wife Johanna and I would
visit Helsinki for two to three weeks at a time. I enjoyed these trips,
but they were always jam-packed with get-togethers with friends and
family. As a result, we could only realistically see a given friend or
relative once while visiting Finland.
Even though I understood our time crunch, I couldn’t keep
myself from saying “I would love to meet up again” at the end of each
visit.
The Americans I know are in the habit of saying things like
“Come on over anytime!” or “Keep in touch!” when we know it will be
difficult to follow through on such sentiments. But to refrain from
using these warm words would almost seem impolite. So, on one visit to
Finland, I wielded this strategy—and it backfired, leading to the
following exchange with my wife:
“Tim, I just spoke with my mom. Her friend is still waiting to
hear back from us. Did you really say that you wanted to meet up again?
You know we don’t have the time.”
“I never said I wanted to meet up,” I explained. “I just said ‘I’d love to meet up again.’ It’s like an expression.”
Johanna was not satisfied with that. “Tim,” she said, “you
can’t speak like that here. In Finland, people take you at your word.”
Since that day, I’ve endeavored to say only what I mean.
3. I don’t leave food on my plate.
After returning to school from Christmas break this year, I
found an official announcement on the whiteboard of my teachers’ lounge.
Its message was straightforward: “No bio waste.”
In January, my school launched an initiative to combat leftover
food, dubbed the “Eat What You Take” campaign. The methodology: remove
the school’s compost bin. Now, when a student (or teacher) clears his
tray and has food on his plate, there’s nowhere to ditch it. In the
cafeteria, the only available receptacle for the 450 people in my school
is a small container the size of a beach bucket, but it’s not for food.
It’s only for dirty napkins.
Under this new policy, students who have food remaining on
their plates have two options: take a seat and polish off the leftovers,
or take a bold step into the kitchen and issue an apology to one of the
lunch ladies.
I’ve never seen or heard of anything like this in the United States. But I have heard of American kids wasting a lot of school food. To take one example: In a study
of Colorado elementary- and middle-school students conducted in 2010,
those observed in elementary school, in the authors’ words, “wasted more
than a third of grain, fruit and vegetable menu items.”
As for me, I learned my lesson last year when my sixth-graders
caught me throwing away nearly half a plate of food. I had severely
miscalculated, taking too much food without having enough time to
stomach it all. Walking back to our classroom, I knew I’d need to make a
slight change to my lesson plan. I’d start with a public apology.
4. I don’t take coffee to go.
Americans have a reputation for doing things on the go:
breakfast in the car, lunch at a desk while catching up on email and, of
course, coffee on the run. “America runs on Dunkin’,”right?
In Finland, my experience is that people are more likely to
slow down when they drink coffee. They sit. They sip leisurely. I often
catch them staring into space. It’s no surprise then that Finns consume nearly twice as much coffee as Americans.
And now I’ve become one of those coffee-drinking space cadets.
But recently, I had an American relapse. I needed to rush out of the
apartment, and I didn’t have time to sit down for a cup of coffee.
Frantically, I rummaged through the shelf that held our cups.
Eventually, I found one silver to-go mug, but the cover was warped. And
when I poured the coffee in, the bottom of the mug started to hiss and
form tiny bubbles.
I shouted gruffly to my wife, “Why don’t we have one decent thermos in this house?”
Johanna snapped back, “Because we live in Europe. And Europeans don’t take coffee to go!”
5. I don’t feel uncomfortable in my own skin.
In the land of 3.3 million saunas, it is inevitable that you will eventually find yourself naked with people you don’t know—and not care in the slightest.
I didn’t realize that I had reached this level of Finnishness
until this fall. A close friend from New York was visiting, and I
insisted that on his last night in Finland he join me for a trip to one
of the city’s public saunas. I was convinced that he would fall in love
with this Finnish pastime, but I was wrong. Very wrong.
I explained that Finns go naked into saunas, but there are
separate ones for men and women. The activity of taking a sauna is not,
in any way, sexual. When we were in the changing room, I smiled and
remarked to my friend, “This is where we leave the towels, man.” He was
not amused. Clutching his towel around his waist, he growled, “No way.”
Unfazed, I hung up my own towel and strolled into the sauna
Finnish-style. I found a spot on the top platform along with another
naked man. A few moments later, my American buddy timidly opened the
door and located a spot on the lowest bench, still gripping his towel as
if his life (or manhood) depended on it.
He lasted about three minutes before declaring “enough” to me
and the other naked strangers in the dimly lit room. I couldn’t help but
laugh. I stayed seated—in silence, of course.
