(melodic music)
- So, I hope you like maps,
because today we're taking a deep dive into borders.
We all know that political borders
between states, countries, regions,
they have a lot of power over us.
They affect our wellbeing, our economic potential,
our loyalties.
But there's another set of boundaries
overlaid on those political ones.
Timezones.
We don't think much about those borders
unless we cross them, by travel or by phone,
but we should, and to prove it we have
a couple of very different stories
about how time zones can also affect our health,
our money, or our very identity.
Both these stories hinge on one odd question.
You know which time zone you live in,
but where inside that time zone are you?
The world today is divided into 24 strips of longitude,
one for each hour of the day.
Each zone is theoretically 15 degrees of longitude wide.
Before time zones existed, communities kept time
largely via one shared standard; the sun.
Today there are two standards;
what the sun says and what your time zone dictates.
And they can disagree.
Take Europe.
In theory, this is what you might expect
the Central European timezone to look like.
It's roughly 15 degrees wide.
In the middle your watch would strike noon
more or less when the sun hits its highest point.
If you travel to the west the sun would be
a little delayed in reaching you,
so solar noon might be 12:30 by your watch,
or 11:30 on the eastern end.
Point is, you'd never be more than 30 minutes
out of syn with the sun.
But that's not the actual time zone.
This is.
In practice, time zones are sloppy,
so disparities between clock and solar time
can be much worse.
If you live in the Galicia region of Spain,
solar noon could hit you around 1:45 p.m.
And around the world we see that
lots of time zones are a mess.
Political borders make many too wide
and lots tend to skew west.
The most extreme might be China.
It's all one time zone,
though it's wide enough to span five.
But we'll come back to that in a bit.
Time zones are wacky, but we promised due consequences,
so here's one, your health.
To help explain, we call up an expert
with a pretty cool title.
- So my name is Eva Winnebeck, and I'm a chronobiologist.
- Chronobiologists study the ways
that our bodily rhythms synchronize
with the day and night cycle.
Our sleep patterns, hormones, digestion,
blood pressure, temperature, you name it,
they're all governed by internal clocks
that sync to the sun.
They're called our circadian rhythms,
circa-dies or about a day in Latin.
But modern life throws a monkey wrench
into that careful rhythm.
- Well we hide in buildings during the day
and at night we switch on the lights,
so we have very little difference between day and night
that our biology can interpret.
So we are not so well aligned anymore with the sun.
- This scrambling of signals tends to keep us up at night,
depriving us of sleep and skewing our schedules later.
That's a problem no matter where you live.
But, here's where time zones matter.
If you live on the eastern end of your timezone,
the sun wakes you up earlier in the morning,
and it helps you get onto an earlier schedule.
But, in the west, the sun rises later.
It worsens the late schedule that many of us
are already on.
And the bigger the time zone, the more extreme the effect.
Chronobiologists have a term for people
living at odds with their biological clock.
Social jetlag.
And it's been correlated with higher risks
of health problems.
Cancers, diabetes, obesity.
Lots of issues usually associated with aging.
A few studies have tied these risks directly to timezones,
meaning the timezone border itself may reflect
a health divide in an otherwise identical population.
- So if you live on the eastern end of a time zone,
just bordering the western end of the prior time zone,
you have an advantage over your neighbors.
- Other studies have even calculated an economic cost.
One suggests that there's roughly a 3%
difference in wages across zone borders.
The authors think that it's likely linked
to the effect of sleep deprivation on work performance
and absenteeism.
That same study found that residents
on the western edge of a time zone
rack up an average of $82 more
in health care costs each year.
To Eva, this all speaks to what we have control over,
and what we don't.
- So we thought we humans are...
We are so beyond our biology, we can fight our biology,
we don't need to listen to our internal clock,
we are in charge.
But unfortunately in turns out this is not the case.
- There's one other consequence we came across
that's very different from the others.
It's about that huge single timezone in China.
Since 1949 the entire country has followed Beijing time,
centered here.
And as we know, that's not good news for Western China.
- This is the representation of the central government's
ill advised policies.
- Mirshad Ghalip is a native of the Xinjiang region
of Western China, though he's now studying
linguistic anthropology in the US.
Xinjiang is so dramatically far from Beijing
that locals there have traditionally done
something equally dramatic.
They've adopted their own pocket of unique time.
- I grew up using Xinjiang time, or local time.
It's two hours behind Beijing time.
- [Cory] Xinjiang time sidesteps all the problems
that come with living in an extreme timezone.
The social jetlag, the health issues.
It's basically the locals opting out.
But there's another wrinkle.
Mirshad is Uyghur, an ethnic group in Xinjiang
that's distinct from the Han Chinese
ethnic majority across China.
And over the years, more and more Han Chinese
have moved to Xinjiang,
bringing with them a different culture and Beijing time.
- Whenever there's interaction between,
you know, like Uyghur and Han Chinese,
especially when there's like time involved,
we automatically, we're used to like converting
whatever time that they're telling us to Xinjiang time.
- Essentially two independent times exist in Xinjiang,
and following one or the other
has become an identity marker.
A connection to either the local Uyghur community,
or to the central government in Beijing.
But there are larger forces weighing on Xinjiang time,
and in the past few years the whole region's been swept up
in a dire and a volatile situation.
Starting in 2016, the Chinese central government
has asserted extreme control over the Uyghurs in Xinjiang.
Locals have been subjected to surveillance,
and even mass internment at the hands
of the Communist Party.
With these developments, the use of Xinjiang time
could draw unwanted attention to locals,
and Mirshad fears it could invite
reprisals from the authorities.
- There might be a lot, maybe the majority of the Uyghurs,
at least switch their time on their watches
or their phone to Beijing time,
just to avoid trouble.
- One researcher we spoke to even raised the idea
of these distinctions of time being weaponized.
And 2014 assailants carried out an attack
on the market in the city of Urumqi in Xinjiang.
Killing dozens and injuring almost a hundred,
both the where and the when of the attack were notable.
- The perpetrators purposely targeted that market
because it was a market frequented by Han people
and it was a market that appeared to open and close
according to Beijing time.
- Crucially, the attack occurred first thing in the morning,
just before 8 a.m. Beijing time,
or 6 a.m. Xinjiang time,
which raises the possibility that the attackers
chose the time to target Han Chinese
and spare the Uyghurs.
- Uyghurs wouldn't be up that early
to go to a morning market,
so it'd been about 6 a.m. Xinjiang time,
but a very normal time for someone
who was operating on Beijing time
to go to a market.
- It's not clear how imperiled Xinjiang time
actually is these days.
For now, it remains a curiosity
that Mirshad hopes will endure.
- I think it will survive, but it's definitely under attack
and it's definitely threatened.
But I'm hopeful, I think it'll survive.
- So with these stories in mind,
here's what we're not saying.
That time zones are the cause of cancer,
economic waste and authoritarian abuses.
But studying time zones does reveal larger societal issues,
like our modern inability to go to bed at night,
and it leads for a recommendation we heard over and over,
that more flexibility in our daily schedules
could do a lot of good.
Allowing wiggle room within timezones,
relaxing rigid work schedules.
It's not a cure-all, but it will make for healthier
and freer people.
- I mean if we all didn't have an external schedule
which we have to work to,
we could all fall asleep when we can and want to
and wake up when we can and want to,
and that would really be the real freedom.
- Hey everyone, that's for watching.
I know we didn't cover daylight savings in this video,
although there are a lot of feelings about that.
But hopefully we'll cover that topic in March.
As always, thanks for watching,
and don't forget to like and subscribe.
- [Male] Don't hold us to it.