In this video, we cover hypertension. We’re going to deal with things like Cardiac Output, peripheral resistance, stroke volume and heart rate, and talk about how those values are related to blood pressure. We also deal with the symptoms of hypertension.
Transcript of Today’s Episode
So, we’re going to be talking about hypertension. But, before we kind of get into to that, I want to talk a little bit about, just a brief review of how blood is coming to the heart and where it’s going from there.
We have blood that’s coming back to the heart. That is going to be deoxygenated blood. I’m not going to do a full pathway because that’s covered in other videos. But then, it goes to the lungs. When it goes to the lungs, it’s going to pick up oxygen and then, it’s going to come back to the heart.
The ventricles are then going to contract. This left ventricle here is going to send blood out to the body via these major vessels that are coming off of the aorta. Now, that blood is going to be oxygenated so, it can go to the organs and to the places that needs it in the body and it can deliver that so that, those organs can do what they need to do.
I want you to picture one of the arterioles. Actually, I’m going to draw an artery, let’s go ahead and draw an artery here, and then, I am going to show blood coming through it. I’m going to show that we have red blood cells and with that, of course, we’re going to have plasma and a number of different things traveling through these blood vessels. This is one of the major blood vessels.
What I want you to understand is when the heart is beating, it is allowing that blood to move with a certain amount of force and that is exerting pressure on the walls of the blood vessels. It’s pushing in these directions but, as a result of the contraction of the ventricle, it’s applying force and applying pressure to the walls of those arteries.
Now, if I were to look at a graph that’s showing the pressure on the Y axis, in millimeters of mercury (mm Hg), and then, time on the X axis, what I would see, (let’s stick with red since we’re dealing with blood), what I would see is that there’s going to be a fluctuation in the amount of pressure. So, it’s going to look something like this.
All right. Let’s say this is in a major artery in an average individual and it’s going to have these high points which are going to be here and we have these low points. I’m going to say that’s around 120 mm Hg and 80. So, this is 120 over 80. That’s the average that we always hear about.
This high point is during that ventricular contraction and this low point is during ventricular relaxation. Now, in a situation of hypertension, you got to think about what this means.
“Hyper” that’s a prefix that means “over or above” and this “tension” has to do with the force that is applying tension. It’s causing it to stretch or elongate or something of that sort. In this case, we’re dealing with the pressure that is being exerted on the walls of the arteries.
So, in an individual that has high hypertension, which means “high blood pressure,” we would expect to see something that looks like this. (Let’s do it in a cyan color). So, it’s going to be significantly higher than that average 120 over 80. Let’s say this individual is around 145 over 100 or something of that sort. I drew that a little higher here but, you get the point. Significantly higher than normal. This is high blood pressure. This is hypertension.
Now, why is this such a big deal? I’m glad you asked. It’s a big deal because we mentioned here that you’re applying pressure on the walls of the vessels. And, if that pressure is very high for a long period of time, a sustained period of time, that can actually cause damage to the blood vessels.
If you damage those blood vessels, that’s going to affect the ability of the blood to go to the target location and that is not a good thing. So, I want you to imagine… Let me stop saying “imagine.” I’m just going to draw it for you. This is a larger artery.
But then, we have some little arterioles or even the capillaries that are significantly smaller. The lumen, the space in between can be as narrow as one blood cell. So, in some locations, we have these capillaries, in many locations we have these capillaries. They are actually moving through almost in a single file because of how small those capillaries are.
And those are going to be even more susceptible to damage if you have high pressure for a sustained period of time. So, of course, this is not a situation that you want to have.
Types of Hypertension
Now, there are going to be two main categories that I want to talk about. There are other ways of classifying it but, I’m going to say that there are two kinds of hypertension.
Those two kinds are going to be:
- Primary or you can also call that essential hypertension;
- And then, there’s going to be (you guessed it), it’s going to be secondary hypertension, and I’ll define this one first.
Secondary hypertension has to do with high blood pressure, of course, but that’s when there are some identifiable cause. So, you might see that an individual has hypertension but, when you do a number of other tests, you might see that there’s kidney dysfunction. If there’s damage to the kidneys, that can actually lead to high blood pressure and that would be secondary hypertension. So, that’s one example.
With primary hypertension, there is no specific medical cause that you can identify. The blood pressure is consistently over 140 over 90 or above, and that is considered primary or essential hypertension if it’s sustained.
Signs of Hypertension
So, what are going to be the signs of hypertension, and this is where things can get a bit complicated. The reason it can get a bit complicated is because it’s usually asymptomatic until it gets to the advanced stages which is not a good thing because if that individual isn’t going in for regular check-ups, they don’t know they have hypertension. They might feel some vague and non specific symptoms, and some of those symptoms, (let’s draw it in red because it’s bad), some of those symptoms might be famous like fatigue, malaise, that feeling of “I just don’t feel good,” light-headedness, headaches… These are some of the symptoms.
Now, do you notice that these are quite regular symptoms? How often do you feel fatigued or you’re just not feeling that well or maybe you’re light-headed, do you think high blood pressure? Not necessarily.
So, it can often go un-diagnosed until it’s very advanced. Now, how do people notice that they do have high blood pressure?
They might go for regular checkup for example, and when you take your blood pressure, you notice that it’s a little higher than normal and you take it at a later occasion and you notice it’s still higher than normal, and maybe you do three readings in one month, where you go to the doctor and they check to see what your blood pressure is, and it’s consistently high, that is an indication that something can be wrong with that individual in terms of hypertension.
Now, how do you prevent this? How do you prevent hypertension? You don’t want this to be the case. You want to be in good health.
Well, a key to that, let’s get rid of some of this here, a key to that is being in good health. So, in terms of prevention, there are a number of strategies for preventing hypertension. Of course, anything that has to do with general cardiovascular health. I’m dealing with things like regular exercise, aerobic exercise, that’s going to of course, help with general cardiovascular health; maintaining your body weight; watching sodium intake, so salt. That plays a role and in a later video, we’ll talk a little bit about sodium and how that affects hypertension; eating well, just generally eating well, fruits and veggies, getting the right amounts of fruits and veggies; and also, regulating, and this is a big one, regulating stress. That is also going to play a significant role because there can be some neurogenic effects of stress on the cardiovascular system that can cause hypertension.
So, these are some of the preventative measures that can be taken so that, you minimize that risk of hypertension.
That’s it for this video. In another video, we’re going to talk more specifically about the mechanisms.