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Health and medicine
Course: Health and medicine > Unit 3
Lesson 5: Hypertension- What is hypertension?
- Intro to hypertension (Pressure, flow, and resistance)
- Intro to hypertension (systolic and diastolic blood pressure)
- Stages of hypertension
- Hypertension types and causes
- Primary hypertension
- Secondary hypertension
- Hypertension effects on the blood vessels
- Hypertension and blood vessel damage
- Hypertension effects on the heart
- Hypertension and heart damage
- Complications of hypertension
- Hypertensive crisis
- Diagnosis of hypertension
- Treatment of hypertension
- 4 lifestyle changes to help manage hypertension
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Stages of hypertension
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Video transcript
- (Voiceover) If you've ever
gotten your blood pressure measured before, I'm sure
you've heard a number like 120 over 80, right. Well, what do those two numbers mean? Well, let's start with the
units cause these aren't just numbers, right. Usually, it comes along
with units like mmHg which mean millimeters of
mercury, where the Hg is what's used to abbreviate mercury. I know, why Hg, right? Well, it's named after this
Latin word for liquid silver, so it's essentially Latin. And so, millimeters of mercury
is the standard unit used to present somebody's blood pressure. Okay, so this first number, this top number is known as
your systolic blood pressure. Remember that systole is
the phase of the heart cycle where the heart contracts
and pumps out blood or simply during a heart beat. So, you've got your two ventricles, your left and your right ventricles, and when those squeeze and get
smaller, they actually eject blood out to your
circulatory system, right. And when this happens, when
the blood is forced through the blood vessels, pressure
is going to be generated in those blood vessels,
and this is what we call your systolic blood pressure. The lower number, in this
case 80 millimeters of mercury is called the diastolic pressure. Now, we can figure out
what that is by its name. It's the pressure in the
blood vessels during diastole. Again, remember that diastole
is when the heart is relaxing. So this is the pressure in the
blood vessels between beats when the heart's relaxing. So, it's like contraction
systolic pressure, and then relaxation diastolic pressure. Pretty easy. So I'm going to draw out these two gauges. One's for systolic pressure, and the other's for diastolic pressure. So let's say that my blood
pressure was measured at 115 over 75 millimeters of mercury. So I'm right about here on our gauge. Really anything sort of below
120 in the systolic range, we're just going to draw
as like this green zone. So your sort of safe from
hypertension in this zone. Now, that's not to say
that like a pressure of 15 millimeters of
mercury is a good thing. What I mean is that you
wouldn't have hypertension or you wouldn't have high blood pressure. So usually around 120
is considered an average systolic blood pressure. Along the same lines, right around 80 millimeters of mercury
on the diastolic side, while the heart is relaxing,
is considered average on the diastolic side. And so, if it's below 80
millimeters of mercury, then we'd say that there
would be no hypertension. So this again is in kind of the
green zone for hypertension. So now let's say that my
pressure was a little higher, maybe 130 over 85. So over here on the systolic side, we're above the green zone now. So in this zone, up to about
140 millimeters of mercury, it's still not hypertension, but it's like it's getting close. It's like we're getting there. So let's make that zone yellow,
and this zone actually is referred to as prehypertension. So it's like before hypertension. And so the same goes
for diastolic pressure. Our yellow prehypertensive
zone or stage is between 80 and 90 millimeters of mercury. Now, it's important to note
that these yellow zones aren't like this hard and fast rule. It's more based on averages
and is like this sort of warning sign that the
blood pressure is maybe slightly elevated, and
it's possible it could lead to hypertension in the future
especially if this is combined with unhealthy lifestyle like
no exercise or poor diet. Okay, so with that said, in
general, hypertension is defined as a blood pressure
greater than 140 over 90. So let's draw that as this
kind of reddish zone above 140. So if my blood pressure was 150
over 100 which is right here on the systolic and right
here on the diastolic, we see that, that would be
considered hypertension, right. So to be more specific, though,
that would be considered stage one hypertension, which is this zone on the systolic side
from 140 to 160 and then, over here on the diastolic
side from about 90 to 100. Now there are only two
stages, so stage two is really anything above 160 on the systolic side and 100 on the diastolic side. So for example, again, my blood
pressure was 170 over 110. That would be stage two hypertension. Now, let's say my blood pressure
is measured at 150 over 85. Okay, I can figure that out. Looks like over here
it's 150 so that falls in to stage one hypertension,
but then over on the diastolic side 85 is in
the prehypertension stage. What gives? Is that possible? Yeah, absolutely, we even
have a special name for this, and it's called isolated
systolic hypertension. That sort of makes sense though, right, because the hypertension is isolated to the systolic blood pressure. Usually, this is described
as systolic blood pressure in the stage one or above
zones, so above 140, and then a diastolic pressure
below the hypertension zone. This sort of isolated systolic
hypertension is more common in the elderly and is actually
associated with an increased risk of cardiovascular complications. I'm sure you can see where
I'm going next, right. What if my blood pressure
is measured at 130 over 105? So I'm in the prehypertension
range for systolic and stage two hypertension for diastolic. As you probably guess, this is known as isolated diastolic hypertension. So the hypertension is limited to the diastolic pressure only. This one is actually more
common in younger patients that tend to be obese or overweight. However, it's not typically associated with underlying
cardiovascular complications like isolated systolic hypertension is.