What is hypertension? | Circulatory system diseases | Health & Medicine | Khan Academy
Aug 24, 2023
What is hypertension? | Circulatory system diseases | Health & Medicine | Khan Academy
Learn the categories of hypertension for systolic and diastolic blood pressures. Rishi is a pediatric infectious disease physician and works at Khan Academy. Created by Rishi Desai.https://www.khanacademy.org/science/h … https://www.khanacademy.org/science/h …www.khanacademy.org , join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything. https://www.youtube.com/subscription _…
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0.953 -> Let's talk about hypertension.
2.203 -> And I'll write that
here, hypertension.
6.28 -> And hypertension basically
means high blood pressure.
11 -> And we actually categorize
it in different groups.
13.29 -> So let's use my blood pressure,
115 over 75 as an example.
19.38 -> And I had drawn a
small figure for you
23.14 -> where I had blood
pressure on this side
25.4 -> and I had time on this side.
28.28 -> And I said at my blood
pressure does something
30.2 -> like that, where
the peak is 115.
33.11 -> This is the systolic
blood pressure.
37.31 -> And I said that the lowest point
is going to be, for me, 75.
42.16 -> And that was my
diastolic blood pressure.
45.934 -> And we know everyone has a
different blood pressure.
48.1 -> So let's organize blood
pressures into groups.
50.49 -> Let's say, let's figure
out what group goes where.
53.25 -> And so, to do that, I'm going
to draw a couple number lines.
56.2 -> So let's imagine that I
have, here in brown, I'll
59.96 -> do my systolic blood
pressure on this side.
63.15 -> And I'll do the diastolic
on the other side.
65.36 -> I'll do diastolic over here.
68.5 -> And we're going to actually
put them next to each other.
71.56 -> And I'll try to make about
the same size, like that.
76.65 -> So let's say this is
really high pressure.
78.97 -> This would be like 200.
80.25 -> And this is all in
millimeters of mercury.
83.6 -> 200 millimeters of mercury.
85.18 -> And at the very
bottom would be 0.
89.61 -> So let's make them
kind of the same.
93.4 -> And that means that up
here would be about 100.
98.03 -> And this would be about--
let's say this is 120.
103.26 -> This would be about
140, let's say.
106.2 -> Maybe this is 160.
108.676 -> And this is 180.
112.45 -> And I'm going to do
the same thing here.
114.58 -> Let's say this is about
100, except this time I'm
116.795 -> going to go the other side.
117.92 -> Let's say this is about
80, and this is 60, 40, 20.
126.35 -> Maybe I didn't draw it as well,
but I think you get the idea.
130.69 -> So this is my number line.
132.51 -> And the reason I drew the
systolic numbers higher
135.126 -> than the diastolics
is because we
136.5 -> know that generally speaking--
or not generally speaking--
138.9 -> always the systolic
pressure is going
140.26 -> to be higher than the
diastolic pressure.
141.968 -> So that's why I
separated it out.
144.36 -> But you can imagine
that these numbers go up
146.26 -> and these go down.
147.009 -> I'm just being lazy
not drawing it all out.
149.49 -> So let's say that
my pressure is 115.
153.672 -> This in my systolic pressure.
154.88 -> Now let's do that one first.
156.34 -> Where does that fit?
157.88 -> Well, on this number line,
115 would be about right here.
161.86 -> And actually anything
below 120 is actually
166.267 -> kind of in the green zone.
167.35 -> And this goes all
the way down, to 0.
170.85 -> So let's say my
systolic was 97, or 103.
176.28 -> That would all be
in the green zone.
177.792 -> And what I mean by
that is, I would
179.25 -> say I do not have hypertension.
180.86 -> I have no hypertension.
183.13 -> So that's kind of
a nice, safe, area
184.83 -> to have your blood pressure
in, in terms of hypertension.
188.78 -> Now for diastolic pressures, we
know that diastolic pressures
192.65 -> are the low range
of a blood pressure.
195.22 -> And so those numbers
are going to be lower.
197.82 -> Here, anything below
80 is considered
200.97 -> in that safe green zone.
203.1 -> So below 80 is where
you want to be.
205.82 -> And I want to be
very specific, I
208.04 -> don't mean to say that a blood
pressure of 5 would be good.
211.8 -> What I mean is that you
don't have hypertension.
213.9 -> So you don't have
high blood pressure.
217.305 -> And that's where it's different
from having low blood pressure.
219.93 -> So just for right now, the green
zone in terms of high blood
222.47 -> pressure.
224.06 -> Now, let's say my
systolic blood pressure
226.61 -> was a little bit higher.
227.61 -> Let's say it's between 120
and 140, somewhere in here.
232.44 -> Then I'm in the yellow zone.
234.05 -> And that yellow zone means
that I don't have hypertension,
237.11 -> but I'm getting there.
238.27 -> So I'm getting closer, and
this would be prehypertension.
242.9 -> And on the other side,
on the diastolic side,
246.19 -> we use 90 as a cut off.
247.89 -> So I'll write in 90.
249.3 -> And anything between
80 and 90 would
251.6 -> be kind of in that yellow zone.
253.84 -> And that's your
prehypertension zone.
256.76 -> It's prehypertension.
258.309 -> So you're still not there yet.
260.81 -> Now in terms of high
blood pressures--
262.427 -> again, you don't want
high blood pressures--
264.26 -> but in terms of getting
there, if you're above 140,
267.64 -> you have hypertension.
268.95 -> So this zone in here,
140 to 160 in particular,
272.85 -> is considered stage
one hypertension.
278.39 -> And between 90 and 100 for
diastolics, that would be
282.24 -> stage one.
287.97 -> And now if you have
something above 160
290.56 -> for your systolic
blood pressure--
292.88 -> so I'll just say
above 160, and that
294.78 -> means even higher than
200, so if let's say
296.892 -> you have 201-- that
would be stage two.
301.33 -> So you can see that
the higher you go,
303.19 -> the higher your stage number.
305.14 -> And the same is
true on this side.
306.93 -> So let's say you have a
really high diastolic blood
309.38 -> pressure, well above 100.
313.11 -> You'd have stage
two hypertension.
317.04 -> All the way down there,
this is stage two.
321.647 -> So I'm just going to do a
couple quick examples for you.
323.98 -> So let's say-- I'll do them
in yellow, different color--
326.56 -> let's say that you
have 145 as a systolic.
335.81 -> And your diastolic
is, let's say, 87.
341.921 -> Well, 145 is right here, right?
346.38 -> And 87-- actually, let me
do it the same color just
349.55 -> to be consistent.
351.28 -> So 145 is right here.
354.79 -> And 87 is in here.
358.06 -> So your systolic pressure
is stage one hypertension,
362.18 -> and your diastolic pressure
is in prehypertension.
365.85 -> So when you're in different
stages for the diastolic
368.8 -> and the systolic what
you do, the rule,
371.19 -> is that you go with
the higher stage.
373.74 -> So in this case,
stage one is higher.
375.47 -> So this person would
be considered stage one
378.77 -> hypertension.
380.529 -> Now we can do one more example,
just to make sure you get it.
383.07 -> So let's do a different color.
384.32 -> Let's say I'll do
the next one in red.
387.22 -> So you have, let's say
126 over, let's say 101.
397.37 -> Well, this person, 126
is actually right here.
401.04 -> And 101 is right above
the 100 mark, right there.
405.24 -> So this person is
actually prehypertensive
408.88 -> if you're looking at just
their systolic value.
411.43 -> But they're actually in
stage two hypertension
414.27 -> if you're looking at
the diastolic value.
416.66 -> So overall, they're
going to be in stage two,
420.21 -> because the rule, again, is that
you go with the higher stage.
424.605 -> So that's how you
figure out what
425.98 -> stage of hypertension
someone's in.
Source: https://www.youtube.com/watch?v=FBoYigdnLKQ
