Stuff You Should Know - How Blood Pressure Works

Episode Date: August 21, 2008

High blood pressure -- or hypertension -- is elevated pressure of the blood in the arteries. Hypertension results from two major factors. Check out our HowStuffWorks article to learn more about the causes of and treatment for hypertension. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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agency would turn out to be a front for a drug pilot who would claim he did it all for this CIA. I'm Lauren Brad Pacheco. Join me for murder in Miami. Talk about walking into the devil's den. Listen to Murder in Miami on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hey, and welcome to the podcast. I'm Josh Clark, a staff writer here at HowStuffWorks.com. With me as always is Charles W. Bryant. Chuck, what's going on? It's good to be here, Josh, as always. Yeah, yeah, I'm feeling the same way, Chuck. I'm feeling pretty good. So you guys might not know this, but Chuck always kind of keeps me abreast of current events, situations going on in the world. What do you have for me today, Chuck? Today, Josh, I have the cause of death results for legendary

soul singer Isaac A. Yes, the man who scored Shaft died recently in his own home gym. Yes, he did. He died apparently while jogging on his treadmill, which is very sad. Yes, of course. And it looks like the cause of death is a stroke because of high blood pressure. You know, that's funny that you bring that up because I've been wanting to talk about high blood pressure, also known as hypertension for a while lately. I'm feeling like this is a good opportunity to do it, right? Yeah, let's do it. You know, house stuff works, stuff you should know. It's not always just fun and games. Sometimes we want to help people out with a little health advice. Agreed. So let's do that, right? Let's do it. Well, Chuck, this doesn't in any way, shape, or form qualify

me as any kind of medical professional, but I spent a trimester in EMT school. Did you know that about me? It's really? Yeah. Yeah, seriously. I had no idea. I did. And I was terrible at it. For the final exam for the trimester, the instructor brought in some of his former students who are now EMTs and they acted like they were suffering from some sort of terrible medical condition. And we had to figure it out based on the symptoms, right? Well, I am a terrible diagnostician. I landed a victim. I just made air quotes who was choking and I treated her like a burn victim later down. And I think I started doing CPR or something on her. And I knew that I had completely missed the mark when she looked over at the instructor with this, what the heck should I do now expression?

And he's just like, keep going, keep going. So she grabbed her throat and you thought that she had burned her neck? Pretty much. Yeah. Yeah. I failed miserably. But there were a couple of things I learned. One of them was how important it is to take care of the old ticker. I mean, we're getting to be about that age, Chuck. I hate to break it to you. I just reached 32. I'm very depressed about that. But we'll take five on to that, my friend. You'll know how kind of you're pushing 40 now. Pushing. Yeah. And neither one of us are in prime physical condition, right? I think that's a fair assessment. Yeah. Yeah. So I'm no triathlete. No. And I love bacon. I love it. I love it so much. I can't even begin to tell you, right? But one of the problems with

bacon is that fat that we eat and digest gets carried through the bloodstream. And it doesn't always break down like it should. No, it starts to form plaque within blood vessels, right? Which actually can lead to hypertension. Right. And do you want to know how? Well, first of all, I think we should just tell people what blood pressure is, period. Because a lot of people get the blood pressure and they don't understand what that is. Right. It's really simple. Blood pressure actually is all it is is the measurement of the force of the blood going through your arteries against the artery walls. Yeah. Your heart actually creates, it generates an electrical impulse. The electrical impulse travels across the heart and is picked up by the atria,

which is, which contracts, right? Right. The blood is forced out of the heart and into the blood vessels. So there you've got, you've got your systolic pressure, which is the first number on a blood pressure reading, right? Right. It's something over something. And that's, that's the first one, the one on top. And the optimal for a systolic pressure, I think is like 120 for the average healthy adult. Yeah. 120 or under is what you're looking for. Right. Now, to measure this kind of thing, luckily, right, we don't need trepanation or any kind of rectal exam. You can just slap a blood pressure cuff on your arm. Right. And thanks to our good friend, Mercury, we can measure the pressure exerted on any given blood

vessel as the blood carry pumps through it. Right. And I, I personally love those things when you get your blood pressure checked. Ever since I was a kid, I just thought when the, when it constricts around your arm and tightens up and you can feel your heart beating in your arm, I just thought it was really neat. And chances are, if you go to a, a grocery store, a drugstore, you might find me sitting at one of their little machines. It's a great thing. It's a great way to pass the time. Yeah. But it's not actually, I did some research. It's not always the most accurate read. So people need to know this when they get their blood pressure checked by machine at your local Kroger. It may have been accurate when they first installed it,

but it needs to be maintained and recalibrated over the years. So if it's not, it may be off. You might can get a good idea that you should look into it further, but you shouldn't, you know, make any medical decisions based on what you, what you get when you're picking out your hot dog buns and your coleslaw. We hear how stuff works strongly. I advise you to consult a physician for just about anything, including blood pressure readings. But yeah, at the very least, it's, it's kind of a joy to have your arms squeezed by a robot. You never know if, if the thing's going to go berserk and just snap your arm right off. It's kind of a thrill. Yeah. That's part of the fear is that it will take on a mind of its own and sever my arm off.

Right. Yeah. Yeah. I think that's everybody's fear. So what about diastolic? Well, that's the bottom number, right? I think for a healthy adult, 80 is a good reading. So the, the good blood pressure reading, a very healthy blood pressure reading is 120 over 80. That bottom number represents what the, the normal relaxing or relaxed pressure on a vessel is when the heart is at rest, right? When, when the blood's not being forced through, it's just, you know, the hearts at rest blood vessels just sitting there like, Oh, I'm waiting for the next pump. You know, right? So 80 is good. And the thing is, is those numbers can change just a little bit and make some really, you know, it can be,

it can be really bad with just a couple of numbers being off, right? Well, tell me more. Well, I will tell you more, Chuck. Let me tell you about the third kind of pressure readings called pulse pressure. Right. It's not necessarily widely accepted yet, although it's really gaining traction. So pulse pressure is just the difference between the systolic and diastolic pressure readings, right? So if 120 over 80 is optimal health for a blood pressure reading, then 40 would be the optimal pulse pressure. It's the difference 120 minus 80. Gotcha. If it's, if it's a high or if the difference is high, you've got problems. It can mean that your, your blood vessels are hardened, right? That they have a loss of elasticity. There's, there's all sorts of problems

with it. It can also mean that your heart is getting a little too buff, hypertrophy, right? Buff in this case is not good. No, it's good for the bicep, not good for the heart because an overly buff heart can, can fail a lot more easily overworked muscle. Yeah. So we've got the pulse pressure difference. And I read that every 10 millibars of mercury, which is the pressure reading difference actually increases your chance of stroke by like 11%. So it's, so it's important to keep an eye on your blood pressure and, and to keep an eye on whether or not you're, you're hypertensive or prehypertensive. And again, the best way to find that is to just go visit your doctor regularly and get some blood pressure readings, right? Because hypertension, aka high

blood pressure, there's prehypertension, which you mentioned, which is before it's a real problem, but it's when you can really correct it with your diet and things like that. Right. And then secondary hypertension and hypertension or when things get out of hand and when you're in danger of maybe a cardiac arrest or stroke. And then the other thing I want to talk about, which I thought was kind of interesting, was white coat hypertension. Give it to me. This sounds interesting. Yeah, this is when your, your blood pressure actually elevates when you go to the doctor. Oh, from, from being nervous? I'm not sure if it's from being nervous or not, but it's, you have a different blood pressure, white coat obviously is what the doctor wears and

the doctor's office and you at home. And I guess, you know, my easy answer would be don't come to the doctor and you won't get high blood pressure, but that's, that's no good advice. Right. And you should also be wary of any doctor that doesn't wear a white coat. Right. Yeah. Yeah. That's, that's good advice too. That is interesting. They've also found that pregnant women can often demonstrate higher blood pressure just because of their pregnancy as well. It can be normal before the pregnancy. It can be high during the pregnancy and then go back to normal afterwards too. The impression I got was that we didn't have a really good read on exactly why that happens. We just know it does happen. Right. Much like the white coat blood pressure. Exactly. And

I've got some other stats for you. If you just want me to. You know how I feel about stats, Chuck, don't tease me. Give me to me. Well, uh, they did some studies on a percentage of adults, 20 years over that have hypertension or that are taking a medication for hypertension and overall 30% of men and women are falling into that category, which is more than I thought. Over 20, I would think that'd be maybe a stat over 40 or 50. Sure. Women come in right at the 30% mark, men a little bit less, believe it or not, at 28%. And the stat I thought was interesting is that poor people are 30 at 34%, whereas non-poor are 28%. Well, it makes a lot of sense. You know, the poor usually have less access to a healthy diet, right? Usually less time to eat well or

take care of themselves since they're working cheaper packaged foods and are loaded with sodium and sodium and salt. It's a big contributor to high blood pressure. So that kind of does make sense. Well, Chuck, why don't you tell us some ways that we can avoid hypertension? And if you have hypertension, I mean, what can you do? Well, kind of like with everything else a doctor tells you, eat healthy, lose weight, lay off the salt, limit alcohol and quit smoking. Yeah. And I looked into smoking, you know, it turns out that smoking, I thought it would stimulate the heart and would wear it out faster. Turns out that doesn't happen. Smoking actually goes in and injures your blood vessels. That's how smoking can cause heart disease and hypertension,

which I found interesting. But yeah, you want to stay away from the cigarettes, the cigars, any kind of smoking is going to be bad for your heart. Right. And as far as your diet goes, they have something they recommend called the DASH diet. D-A-S-H stands for dietary approaches to stopping hypertension. And what you want to eat is whole grains, poultry, fish, nuts. You want to limit fats and red meat. So not so much bacon, huh? Not as much bacon, steak, stuff like that. I'm doomed. Yeah. It's nice. It's a nice treat, but that shouldn't be your regular... Agreed, Chuck. So what happens if you do have hypertension? I mean, obviously, that there's a lot of medications out there on the market for people who are hypertensive, right?

Yeah. There's a lot of medications, but a lot of these have side effects too. So it depends on how high your blood pressure is as to whether or not a doctor thinks it's worth it to get on these meds and potentially suffer some side effects. So there's a few points here and there they'll probably recommend that you take care of it through diet and exercise. Sure. If you have a real problem, there's all kinds of anti-hypertensive drugs, diuretics, sympathetic inhibitors, calcium channel inhibitors, ACE inhibitors, and they all do a good job, but side effects like sedation, nightmares, depression, vertigo, stuff like that. Side effects? Yeah, those are side effects. My favorite side effect? Death. Yeah. I love it when they say that on

as a pharmaceuticals. Well, you mentioned sympathetic inhibitors. Is that that would have to do with the sympathetic nervous system, right? Yeah. That would control your fight or flight response, correct? Right, which is something that we like to talk about a lot around. We love the fight or flight response. Well, if you do have hypertension and you are being treated for it, take hope. I read somewhere that 64% of people who suffer from hypertension recover from it. They gain control of their blood pressure again. That's good news. Go see your doctor, eat well, quit smoking, watch the booze, all that, and if you want to learn a lot more about hypertension, read Hypertension in-depth on howstuffworks.com and stick around to find out how Chuck and I

know that the world is about to end right after this. Stuff you should know is brought to you by Visa. We all have things to think about. Like say, what's the best site to buy a new leather jacket, or whether to buy the three- or six-megapixel camera? But thankfully, we don't need to think about online fraud, because for every purchase you make, Visa keeps an eye out for fraud, with real-time fraud monitoring, and by making sure you're not liable for any unauthorized purchases. How's that for peace of mind? Safe, secure, Visa. So, Chuck, you want to tell everybody how we're privy to the information that the world is about to end? Well, Josh, it's not because we're smarter than everyone else, because that's not true. It's because we read the article,

Our Frogs on the Brink of Extinction. That's true. Frogs are an indicator species, and when they start disappearing, everybody else at the top of the food chain is in big, big trouble. So, this is something you might want to do a little research on. Go type in our frogs on the brink of extinction in the search bar, howstuffworks.com. For more on this and thousands of other topics, visit howstuffworks.com. Let us know what you think. Send an email to podcast at howstuffworks.com. I'm Lauren Bright-Pacheco. Join me for Murder in Miami. Listen to Murder in Miami on the iHeart radio app, Apple Podcasts,

or wherever you get your podcasts. In 1968, five black girls were picked up by police after running away from a reform school in Mount Megs, Alabama. I'm writer and reporter Josie Duffy-Rice, and in a new podcast, I investigate the abuse that thousands of black children suffered at the Alabama Industrial School for Negro children, and how those five girls changed everything. Listen to Unreformed on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts.