Name: 屏住呼吸10分鐘的漁民。 (The Fishermen That Hold Their Breath For 10 Minutes)
Uploaded: 2021-01-14T10:36:51.000Z
Duration: 9 min 33 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

- I'm taking January off, and while I'm gone, some amazing creators

未來進行式

are going to be taking over this channel.

We start with Rohin Francis, a cardiologist who runs Medlife Crisis.

His video includes footage from his diving trip to Borneo

and a couple of jokes that I am deeply uncomfortable with.

I'm sorry, homo sapiens are just pretty pathetic

who can stay underwater for one or two hours.

some you can actually take advantage of by channelling your inner dolphin.

Others involve a little bit of gentle evolution,

so maybe a bit of a tall order for most of us

unless you're a member of an Asian community who have evolved into real life Aquamen.

There are five ways we can spend longer underwater.

Number one is to increase your tolerance to carbon dioxide.

The first thing that makes you want to take a breath

is the rising level of carbon dioxide or hypercapnia.

"Hyper from the Greek, meaning too much or above,

and the body is so acutely sensitive to any changes in pH,

even though it's tiny, that it starts screaming at you to...

Incidentally, this is why any diet claiming to alkalinize your blood is basically

Now you can improve your carbon dioxide tolerance quite quickly.

I was able to go from about 90 seconds breath-hold

to five minutes with just a few days' worth of snorkelling

and some tips from an experienced free diver.

The next obstacle though is a lot harder to get around

No matter how you die, ultimately it's hypoxia

at the cellular level, i.e. your cells being starved of oxygen,

that is the cause of your inevitable death.

Unlike training your body to become more tolerant to hypercapnia,

increasing your tolerance to hypoxia takes years of training.

And of course, there is a level past which no human can actually go.

So what is the solution for a longer dive?

Well, to maximise oxygen delivery and minimise oxygen use.

The reason that this steak is red is a protein called myoglobin,

which is found in the muscles of pretty much every mammal

However if we were tucking into a steak that came from

a seal it would be almost black in appearance because

they've got ten times more myoglobin than humans or cows.

So why can't we just pack in more myoglobin

The problem with proteins is that when they g--

The problem with proteins is when they get too tightly

packed they start to clump together and lose their function

but marine mammals have evolved a very clever way to deal with this.

Their variant of the myoglobin molecule has a positive electric charge.

As I'm sure you know, positive repels positive

and as a result the proteins can get very close together

Number three is to adjust your blood flow to preferentially supply

the heart and the brain at the expense of things like the extremities

which are much more tolerant to having a reduced blood flow.

And number four is to slow your heart down.

so by reducing your heart rate you're immediately

I've mentioned these two together because they form part of the dive reflex.

Erroneously sometimes called the mammalian dive reflex.

It's actually been found in pretty much every air-breathing vertebrate

And remember, below 200m depth, water is cold

and of course that's where most mammals do their hunting.

I've not tried this before but I filled up a basin with ice water.

I'm going to hold my breath and submerge my face

in the water probably just for about thirty seconds or so

and I'll see if anything happens to my heart rate.

I've got a pulse oximeter that you can see.

So my heart rate has dropped right down to 45.

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屏住呼吸10分鐘的漁民。 (The Fishermen That Hold Their Breath For 10 Minutes)

inevitable

crisis

positive

evolve