This man is about to dive 20 m (65 ft)
off the top of a cruise ship.
What will happen to his body
when he hits the water?
Well, luckily for him, and others,
the impact of hitting the water
wouldn't be the worst part of going overboard.
The worst part
would be what would come next.
Being lost at sea.
Even if you're wearing a life jacket,
surviving all alone in a giant body of water
until someone rescues you will not be easy.
We say 24 hours because
it's a nice familiar number,
but the reality is that you'll be lucky
if you even last that long.
Hypothermia can set in within minutes,
and dehydration and exhaustion
would soon follow.
One crucial thing to keep in mind
is that you'd be surrounded by saltwater.
You can't drink it,
but it could save you from drowning.
It's a lot easier to drown in freshwater
than it is to drown in saltwater.
About 90% of all drownings occur in freshwater.
Not only is saltwater more buoyant
than freshwater,
but it's also safer to inhale.
If you're going to drown in saltwater,
it's because the water you inhaled
into your lungs
stopped you from getting oxygen
and expelling carbon dioxide.
But with freshwater,
it can be a little more complicated.
Freshwater can kill you
even after it's been removed from your lungs.
When you inhale saltwater,
the higher salt concentration
prevents the water from
crossing into your lung tissue.
When you inhale freshwater,
it can enter unprotected lung cells,
and make them swell until they burst.
This can lead to such severe damage
that you might not recover,
even after the water is removed from your lungs.
But saltwater has its drawbacks too.
If you only have saltwater around you,
dehydration can be a major threat.
If the hot Sun is beating down on you,
dehydration can begin in about an hour.
You'll be losing water from sweating,
urinating, and even breathing.
As dehydration sets in,
you'll start to feel extremely thirsty,
dizzy, confused, and fatigued.
None of that will raise your chances of survival.
If you're lucky, it will rain.
Rainfall will provide a good source
of drinkable water.
Just lay on your back and open your mouth.
But if you don't get any rain,
you'll need to be a little more creative.
Try to catch a large fish.
If you're successful,
then all you have to do is eat its eyes.
Big fish eyes are full of a watery liquid
that will surely quench your thirst.
Yes, I know. It's gross.
But there's no time to think about that,
because you still have to worry about
hypothermia.
Generally,
you can expect to survive in 5 °C (41 °F)
water for 10-20 minutes
before your muscles will get weak,
and you lose your strength and coordination.
This happens because
the blood moves away from
the furthest parts of your body
and towards the core.
The best way to prevent hypothermia
is to pull your knees up to your chest,
and keep them there,
so you can retain as much heat as possible.
The less you move around
is also better for conserving your energy,
and not attracting predators.
As you've probably gathered
from the past few minutes,
finding yourself in this scenario
would be very bad.
Your best bet at surviving in the sea
is to avoid getting into this situation
in the first place.
If you're going out on a fishing trip,
or a boat,
remember to tell people
where you're planning on going,
and when you're supposed to be back.
Technology is making it easier
to find people who get lost in water.
But the more information, the better,
when it comes to rescue missions.
You'd want to be rescued from the water
as soon as possible,
because being submerged in water for
any longer than 24 hours
can lead to your skin breaking down.
If this happens, you’ll have open sores,
and you would have a greater risk of fungal
and bacterial infections,
even if the water is completely sterile.
Don't believe me?
Well, maybe you should test it out by sitting
in a full bathtub for a few days straight.
But that's a story for another WHAT IF.