and I was told that my blood pressure was 115/75.

血圧を測ってもらいました。

So I thought we would talk about exactly what this means and try

115と75でした。

to figure out how to think about blood pressure in general,

これにはどういう意味があるのでしょう。

using these numbers and this experience

血圧とは何なのか、

as kind of a launching point.

これからこの数字と

So the way I think about blood pressure

血圧の測定を例にとって説明します。

is I always imagine kind of a tube

さて、

and I imagine blood going through that tube.

血圧を考えるときは

And this tube is like a blood vessel.

管の中を

So there's blood trying to get its way

血液が流れるところを想像します。

from one side to the other.

これを血管としましょう。

And on its way, the neat thing that it's doing

血液はこちらから

is as it flows, it's pushing out.

こちらへ流れます。

So it's forcing against these walls,

そして流れるときには

and specifically what I mean by that is there are cells

外の方に向かって圧力がかかります。

and there's plasma, and all that stuff is pushing out

血管の壁を押すわけです。

against the walls of the blood vessels.

血液は

So you've got a force, and that force

赤血球と血漿からできていますが、

is being exerted on the surface area of the blood vessel.

これが血管の壁を

So it's force over a surface area.

押すのです。

And any time you see force over an area,

血液の押す力が、

you know that equals a pressure.

血管の表面に

And in this case, it's a blood pressure

かかるのです。

because it's the blood that's doing that work.

押す力／表面　ですね。

So this is how I think of blood pressure, specifically

それが

as those little blue arrows.

圧力であり、

And the two questions that kind of pop into my mind anytime

つまり血圧です。

I'm thinking about blood pressure

血液が圧力をかけているからです。

are where is the blood pressure being taken,

血圧を想像すると

and when are you taking it?

この青い矢印です。

So let's start with the first question, where?

さて、血圧を考えるとき

And by that I mean where in the circulatory system.

いつも問題になるのは

So you've got the heart-- and this is my Valentine's Day

どこで血圧測るか、

heart-- and you've got the aorta coming off of the heart.

そしていつ測るか、です。

And it's got lots of branches, but I'm

まず測る場所から。

going to just draw one branch, which

つまり体の循環系のどこで測るかです。

is the artery leading off to my arms.

これが心臓。

This is called the brachial artery going off to my arm.

バレンタインのハートです。

And usually, I'd say 90% of the time,

ここから大動脈が出ていて

maybe even more, the blood pressure that you're

枝分かれします。

getting recorded, or the number that's being told to you,

ここでは一つだけ、

is being checked at this point.

腕に伸びる動脈を描きます。

I marked it with a little x because that's

上腕動脈

kind of the upper arm.

腕の方に伸びています。

So that's usually where they're checking the blood pressure.

さて、血圧を測るとき、

And again, they're checking the force

殆どの場合

that the blood is putting on the vessel walls.

この部分で測った数字が

So these little blue arrows.

使われます。

So that answers the where question.

Xとしましょう。

And certainly, you can imagine if I checked

場所は上腕です。

blood pressure let's say at some other spot, let's say over here

ここで血圧が測定されます。

or over here, you might get a different blood pressure

血管にかかる

reading than if I checked it at the yellow x.

血液の圧力が測定されます。

So really were just talking about that one spot.

青の矢印です。

Now the other question is when are you checking it?

どこで測るかの答えが、

So for this, let me show you a little table or a figure,

これです。

rather.

他の場所でも測れます。

So imagine that over time, time is this way,

こことか、こことか。

you have different recordings for blood pressure.

当然違った値が

So this will be blood pressure.

得られます。

And blood pressure is usually measured

普通はこの黄色いところで測ります。

in millimeters of mercury.

それではいつ測るのでしょう？

So I'll write millimeters of mercury here.

ここでグラフを

And let's go from 200 all the way down to 0.

描いてみます。

And I'll use my numbers that I got from the doctor

これが時間軸

the other day to illustrate what I'm trying to say.

です。

So right at that yellow x, at the bottom,

測る時間が違えば、

let's say of my reading I've got 75.

血圧も違います。

So let's start at 75, which is about here.

血圧は普通

As the heart is pumping, the pressure starts building up.

ミリメートル水銀柱で測定します。

And it gets up to about 115.

ここに書きましょう。

So really what is happening is blood

200から

is making its way from the heart as it squeezes towards that x.

0まで。

And as it gets there, the force that it's putting on the walls

私が医者に測ってもらった

is going up, up, up.

血圧を例に

And as it goes up, it goes from 75 all the way to 115.

説明します。

So that all happens during the squeezing part

この黄色のXで

of the heart cycle.

測った血圧は75

We call that systole.

このあたりです。

So this is all happening during systole,

心臓が鼓動すると

which is when the heart is squeezing down,

血圧は上がります。

and we know the heart is a pump.

私の場合は115に

Now from that point forward, the heart begins to relax.

つまり

So at this point, at 115, the heart is now relaxing slowly.

血液が心臓から

And as it relaxes, the pressure begins to fall.

押し出されてXのところへ行くのです。

And it continues to fall all the way out here.

この段階で

And the pressure gets down to about 75 again.

血液の押す力がどんどん上がります。

And this is diastole.

そして75から115に上がるのです。

So this is when the heart is actually

心臓が収縮するときに

taking a break from squeezing and is now refilling,

こういうことが起こるのです。

and we call that diastole.

これが収縮期です。

So I'll call that refilling.

心臓が血液を絞り出したいる

And so during systole, you spend about 1/3 of the time.

時に起こるのです。

And in diastole, you spend about 2/3 of the time.

心臓はポンプのようなものです。

And I'm talking about one heartbeat here.

血液を押し出した後は

So this would be one heartbeat.

ゆるみます。

So it's not 50-50.

115まで上昇した圧力は

And the easy way to remember this

心臓が緩むに連れて下がります。

is in a given day, 24 hour day, I

どんどん下がって

spend about 8 hours working and about 16 hours relaxing,

また75に戻るのです。

or not working.

これが拡張期です。

And so I think of the heart doing its squeezing,

心臓は収縮した後

its work, for eight out of 24 would be about 1/3.

拡張し、血液を再び取り込みます。

Kind of the same as me.

これが拡張期です。

About 1/3 of the time, the heart is squeezing.

血液が心臓に入ってくるのです。

So that's how the heart is spending its time,

心臓の鼓動の1/3は収縮期、

in systole and diastole.

約2/3は拡張期です。

And the pressure is ranging between 115 and 75.

これが一回の鼓動です。

So really it's never just 115 or just 75.

1ドキというわけです。

It's somewhere between the two.

半分ずつと言うわけではありません。

And for example, if I checked right here in time,

これは私たちの一日に似ています。

it might be let's say 85, or here it might be 102,

8時間働いて、

or here it might be 87.

16時間休む。

So it's somewhere between 115 and 75.

心臓も同じです。

So this number I wrote up here becomes the range.

1つのサイクルの1/3を収縮に、

This is the range of blood pressure.

つまり私と同様、

So when I talk about when, it really

仕事に使っているのです。

depends on when in the cycle you're at

心臓の収縮期と拡張期は

and you're somewhere in that range.

こんな割合です。

And when I talk about the where, we

この運動の中で血圧が

know that we're talking about a reading that's

115だったり、75だったりします。

taken in the upper arm.

単に2つの数字というわけでなく、幅なのです。

So those are the two thoughts that

今この位置で測れば

should cross your mind every time you hear a blood pressure

85かもしれません、102かも、あるいは87かもしれません。

recording.

つまり75から115までのどこかなのです。

And of course, the top number, 115 again,

この数字[115/75] はしたがって

is the systolic blood pressure.

1つの幅を表しています。

And 75 is the diastolic blood pressure.

これが血圧の範囲です。