"How to Treat Jet Lag with Light"
Jet lag is a blessing to circadian biologists,
because the disruption of mental
and physical well-being immediately highlights
the importance of their work,
the study of our internal “body clock.”
Much of the general malaise we may
experience on long journeys may just
be so-called ‘‘travel fatigue’’,
which can occur regardless of the time zone,
leaving people feeling disorientated,
generally weary, and headachey.
Dehydration has been blamed.
The air circulated in the cabins
of commercial airlines is pretty dry.
Yeah, it can make your throat,
skin, and eyes feel dry.
But, if you do the math, the maximum loss
of fluid through like breath and sweat
wouldn’t be more than like an
extra half cup; so, it’s not like
you’re in Death Valley or something,
and that calculation assumes that the
passenger would be nude,
and I’m sure they’d charge extra for that.
Of course, giving people salty pretzels
doesn’t help.
The vegetarian option tends to be
healthier, if they’re serving meals,
but you have to specify that
when you book.
BYOF — Bring Your Own Fruit —
is a good rule to fly by,
or unsalted nuts as a snack.
The cabin air isn’t just dry,
but low in oxygen pressure,
about what you’d get 10,000 feet
above sea level, like twice as high
as Denver, and that alone can make
you feel not-so-great.
Then, when you land, if you’ve crossed
enough time zones, you can suffer
from jet lag, which is the temporary
disconnect between the new time
at your destination and that of your
own internal body clock,
which is still on home time.
This is abnormal, since our internal clock
is normally synced to the outside world,
but the symptoms of jet lag go away
as our body becomes hip to the new time.
This usually takes, in days,
two-thirds the number of time zones
crossed eastwards, compared with half
the number of zones crossed westwards.
So, London is like 6 time zones
east away from Chicago;
so, flying there, it may take 4 days
before you’re back to normal,
whereas Londoners flying to Chicago
should get over their jet lag
in only 3 days.
The reason it’s easier to go west,
where the day is longer,
than east is because our internal clock
is naturally set for longer than
24 hours and has to be reset every day.
That’s why they call the daily
rhythm circadian, meaning about a day.
In fact, you can see this in
Major League Baseball performance.
Researchers churned through 40,000 games,
mining 20 seasons and found surprisingly
specific results of circadian misalignment—
jet lag, and, indeed, the problems arose
most after eastward travel with very
limited effects after westward travel,
consistent with the greater than
24-hour cycle length of the human circadian clock.
OK.
But, how do you treat it?
First, you need to figure out
if it needs treating at all.
If you’re just traveling 1 or 2 time zones,
you don’t have to worry about it.
If you’re crossing three or more time zones,
like traveling coast to coast,
it then depends on how long
you plan on staying.
If it’s just a few days, it’s probably
not worth treating it,
since then you’ll have to switch back
as soon as you get back home.
If you have control over your schedule,
it’s better to time appointments
in the new time zone to coincide
with daytime back home.
So, it’s pretty much common sense.
If you travel east, your body will
still think it should be sleeping
in the morning.
So, you should push stuff later,
and vice versa.
But, if you are going to be gone
for a while, you can adjust your
body clock using behavioral methods
and/or drugs, supplements, or foods.
There is only one sure fire way
to avoid jet lag altogether,
and that’s to adapt to the new
time zone before your trip.
However, changing your home sleep
schedule more than a few hours
can be counter-productive
by interfering with your pre-trip sleep,
and you don’t want to be going into
a long trip already sleep-deprived.
Before your trip, you want to
maximize your sleep.
In flight, the recommendation is
to immediately adjust to the destination
meal schedule—easier said than done,
and then, once you land,
you want to try to maintain the
destination sleep schedule.
Try not to nap more than a few minutes,
and you don’t want to be driving around
when your body thinks it’s the
middle of the night.
But, the key to treating jet lag
is light therapy.
Going east, you expose yourself to the
bright light in the morning
and avoid bright light in the evening,
and vice versa going west.
But, it’s more complicated than that.
The advice switches if you’ve traveling
through more than six time zones,
because your biological clock
may then adjust in the wrong direction.
And, it’s even more complicated than that!
The effects of light acting upon
the body clock is only actually during
a specific window around the time
your body temperature bottoms out:
that's usually around 4 am.
You drop from 98.6 down to like 97.6,
even when you’re not sleeping—
it’s just part of our circadian rhythm.
The bottom line is here are the two
cheat sheets you can take
a snapshot of for future reference.
So, for example, if you fly
from LA to London, 8 time zones east,
you’d avoid light between 6am and noon
local time and expose yourself to light
between noon and 6pm local,
and the rest of the day,
it doesn’t matter and
won’t affect you either way.
OK, now but that’s just on Day 1.
On subsequent days, the local times
of light avoidance and exposure
need to be advanced earlier by
1 to 2 hours each day until light
avoidance coincides with when
you’re sleeping.
But, on those first few days
after traveling east, you’ll note
you’re going to want to be avoiding
morning light, which can be difficult,
if that’s when your flight gets in.
One thing you can do is wear
really dark glasses until you get indoors,
but if they’re too dark,
you can’t really drive;
so, that’s where these kind of ugly
orange lenses that block blue wavelengths
can come in handy, preventing the
dip in melatonin you get just
wearing regular sunglasses.
Regardless, the next day, I know there’s
the urge to get out and about,
but that could actually make your jet lag
worse by taking you in the
opposite direction.
What about if you’re flying more
than 8 time zones east?
Then, you subtract the number from 24
and treat it as travel west.
So, a 10-time zone trip to the East,
like New York to Delhi, should be
treated as a westward flight,
requiring a delay of the body clock,
across 14 time zones.
In that case, it would be easy
to get outside and get some sun,
but if you just went 4 time zones west
and need to get light in the
middle of the night, what do you do?
A gadget company came up with like
light-emitting headphones,
the theory being you could bathe
your brain in light directly
through the ear canals.
They stuck them on the heads
of cadavers and did seem to get
some light penetration,
but you don’t know, until you…
put it to the test.
This randomized, double-blind,
placebo-controlled trial demonstrated
that transcranial bright light exposure
via the ear canals could alleviate
jet lag symptoms,
or you could just turn on a lamp.