It’s 2:43am.
And…
I’ve given up.
I’m in my kitchen, taking half a sleeping pill, because three days earlier I spent 23
hours flying across 9 time zones from Sydney to New York City and my jet lag is horrible.
Actually, the worst I’ve ever had.
I’ve been trying for fall asleep for four hours.
It’s now been 7 days since I arrived in New York, I still can’t fall asleep before
2am and I’ve slept through two morning meetings and a dentists appointment.
So in an attempt to unpack my own problems, I started to search why do we get jet lag…
and how can we fix it?
And the answers are wrapped up in some pretty fascinating sleep science.
Now, your body has a lot of ways of keeping time – you have tiny molecular clocks in
most of the major systems in your body.
To keep your body in sync, your brain has a master body clock, which is a group of about
20,000 nerve cells that form a structure called the SCN.
The SCN receives direct input from your eyes - so based on the amount of light you’re
seeing, it sends signals about the time of day to the rest of your body and brain, keeping
your body clock in tune with the world around you.
These signals about when you should be awake and when you should be sleepy are the way
that your brain regulates the timing of your circadian rhythm.
You’ve probably heard of your circadian rhythm before – it’s produced by your
body clock and is your daily cycle of being awake and not awake – and awake and not
awake.
This circadian drive is one process that regulates sleep – the other is your homeostatic drive.
This is your biological urge to sleep and it’s more straightforward – the longer
you’ve been awake, the more tired you get.
You’ll feel the most tired when your homeostatic urge to sleep is high and your circadian clock
is also sending signals that it’s time to sleep.
Normally, these two things should happen at about the same time.
But when you travel across time zones, things get lagged.
Say you shift 5 time zones – like New York to London – Your homeostatic drive is saying
you’ve been awake for ages, so it’s time to sleep, but your circadian clock is like
“oh fun it’s only 7pm it’s definitely not bedtime yet!”
And this disconnect between your homeostatic and circadian drives is why we can’t sleep.
Then we get fatigued.
And have mood swings and make questionable decisions and can’t run as fast and have
different bowel movements.
These are all symptoms of jet lag.
But in some cases, jet lag is worse than others.
Research has found that jet lag is worse travelling east than travelling west.
Which is something I can personally attest to!
This is because it’s easier to delay than advance your circadian rhythms.
Think about how it's easier for you to stay awake when you're tired than to fall asleep
when you're not tired.
In what seems like a torturous experiment, researchers in Australia actually flew their
study participants from Sydney to Qatar for four days and then back to Sydney to look
at the impact between travelling in different directions.
From this, they estimated that the time it takes you to adapt to a new place is half
a day per hour of the time difference west and 1 day per hour of the time difference
east.
Which means that, since the time difference from Sydney to NYC is 14 hours, it could take
two weeks for me to return to normal.
So at this point you’re probably wondering – is jet lag avoidable?
Or am I doomed?
And this is where the fascinating sleep science comes back into it.
Your brain’s master clock will take time to shift, but there are a few things you can
do to speed it up.
If you want to shift your schedule earlier, you need to increase your light exposure in
the morning.
So, set an alarm, and for the love of science, get up and get outside.
Even if you only had a few hours sleep.
Otherwise your sleep cycle will be thrown off for much longer.
And *don’t use your devices before bed* In the hour before you’re planning on sleeping,
keep the lights dim.
Melatonin supplements have been found to help people get to sleep and I’ll link to more
information on that in the video description.
If you want to shift your schedule later, stay up for as late as you can, and if you
wake up early, stay in a dark environment (without using your devices) until it’s
a reasonable time to get up.
And since you have tiny molecular clocks in other organs, try to keep your meal times
on track with your new location, rather than eating constantly or having a midnight snack.
Studying jet lag scientifically is actually really really hard because there are so many
variables – people’s age and fitness levels and gender and medications typical sleep patterns
and distance that they're travelling and direction that they're travelling and this list could
go on forever.
Your brain is a complicated machine – so much so that we can’t cure jet lag.
But research has found a few things we can do to lessen the impact.
Keep in mind that your human body wasn’t designed to fly across 9 time zones in 23
hours.
And in the future, when there's people living on Mars, and commercial space travel and you’re
bullet training across America, there will still be jet lag.