This lesson will cover topics included in Chapter 14-Protecting Your Cardiovascular System, and you'll notice that the second half of this course, beginning with this week, is focused on the relationships between health behaviors and mainly physical activity and different diseases. And so the goals of this lesson are to identify and describe the types of cardiovascular disease and its associated risk factors, and to also talk about how we can use physical activity and other lifestyle health behaviors to reduce the risk of developing cardiovascular disease.
As you can see in this slide, deaths from cardiovascular disease have actually declined over the past few decades, but in 2008 over 30%, or about one in every three deaths in the United States were still attributable to cardiovascular disease, so it's still a huge problem, although we have seen some declines in the prevalence over the past few decades.
And not only is cardiovascular disease a problem in the United States because of the number of deaths that it causes each year, but the total direct and indirect cost of cardiovascular disease and stroke in the United States for 2008 was estimated to be almost $300 billion. $300 billion; that's a lot of money spent on diseases that are, at least in part, preventable through lifestyle behaviors. And so what you can see in the graphs here is that these costs are expected to continue to increase for the projected 2015 through 2030 years, and it doesn't matter what type of cardiovascular disease we're talking about, whether it's hypertension, coronary heart disease, heart failure, stroke, or any other number of cardiovascular diseases. These costs are expected to increase from now through the year 2030.
In Chapter 4 we learned about the healthy function of our heart and our cardiovascular system, and in this lecture we're going to talk about the unhealthy cardiovascular system and the development of cardiovascular disease, and the first thing to know about cardiovascular disease is that it's actually a group of different diseases that affect the heart and the blood vessels, and not a single disease. Cardiovascular disease is a prevalent disease, like we just saw, and it's the leading cause of death in the United States today, and on the next slide we'll see the types of cardiovascular disease that most commonly lead to death.
So on this slide you can see the breakdown of the over 30% of deaths that occur from cardiovascular disease. The majority of those are coronary heart disease, followed by stroke and then high blood pressure and heart failure, diseases of the arteries and other diseases. And so the main take-home point here is that coronary heart disease is responsible for the highest percentage of deaths from cardiovascular disease, but this doesn't mean the others aren't important, and we'll talk about all of these in the next series of slides.
Atherosclerosis is the first type of cardiovascular disease that we'll talk about, and you can see in the Greek word origins here that really we're talking about the hardening of the plaque that occurs inside the artery walls, and this is a very slow, progressive disease that usually develops in early adulthood and then develops over decades and potentially even starts before early adulthood. People are usually asymptomatic, meaning they have no symptoms from atherosclerosis.
Atherosclerosis develops over time and is thought to begin with an injury to the very innermost layer of our artery or arteries, and this begins a cascade of events that involves the interaction between LDL cholesterol, or the bad cholesterols, and our immune system that eventually results in a large plaque blocking the artery, and there's a lot more detail to this sequence, but this detailed description is provided in your text, and you should read that section very carefully.
Coronary heart disease is another type of cardiovascular disease, and as you saw in the pie graph it's the greatest killer of all the cardiovascular diseases. About one in two men and one out of every three women will develop coronary heart disease at some point in their life. It's most commonly the result of atherosclerosis like we just talked about, or the narrowing of the two coronary arteries, the arteries that supply blood to your heart, and when you have narrowing of these arteries, the oxygen-rich blood cannot reach the heart where it's needed to maintain normal function. When that happens it can result in heart attack, angina, heart failure, and we'll talk about these in the next few slides.
Angina pectoris, or simply angina, is chest pain that's due to lack of oxygen getting to your heart muscle, and so the heart is receiving some oxygen, but not enough to function properly, and this angina is something that may or may not occur before someone has a heart attack, so some heart attacks occur with angina and some heart attacks occur without it. Another related term is ischemia, and here we're just talking about a shortage of blood flow to the heart.
A heart attack is when blood flow to the heart is blocked, and we also call this a myocardial infarction, and if you break down that word, an infarct is just dead or dying area of tissue, and so a myocardial infarction is just an area of the heart tissue specifically that is dead or dying. Some of the warning signs for a heart attack include chest discomfort; discomfort in other areas of the upper body, specifically the left arm; shortness of breath; a heart attack could be preceded by a cold sweat; nausea; lightheadedness; sometimes people report just not feeling right. And it's important to note that sometimes women have different symptoms than men, so for example, women are more likely to experience symptoms without chest pain compared to men.
Stroke is another form of cardiovascular disease, and similar to a heart attack in that the tissue is not getting enough blood or O2 that it needs, so it occurs when the oxygen-rich blood flow to the brain fails. So instead of like a heart attack—the blood gets cut off to the heart—in this case, in a stroke, the blood is getting cut off to the brain. And there are two different types of strokes that we talk about. The first is ischemic, and that's caused by a blockage of blood flow, so about 80% of all cases are ischemic, and the second is a hemorrhagic, caused by bleeding, so oftentimes there can be a hole in the artery where there's some seeping of blood, and that occurs in about 20% of all stroke cases, so less frequently but still important to know about.
Strokes can affect any area of the brain, and effects of the stroke depend on the area of the brain that's damaged. They can cause paralysis; they can affect sight, touch, movement and cognitive abilities.
The symptoms of stroke, which often come on suddenly and usually occur on one side of the body compared to another, could be numbness of the face, arm or leg; confusion; the person might have some trouble speaking; they also might have trouble seeing with their vision; trouble walking or dizziness; and a severe headache, again, one that comes on suddenly without any warning or without a known cause. And as you can see in the graphic in this page, it's important to recognize the signs of a stroke quickly and then get to emergency help as fast as possible, because the longer someone with a stroke goes without treatment, the worse the damage to the brain.
Another types of cardiovascular disease is high blood pressure, and high blood pressure is the third leading cause of death for all types of cardiovascular disease and affects about a third of all adults in the United States, and nearly three in ten adults are pre-hypertensive, meaning their blood pressure is elevated above normal, but not to the level considered to be hypertensive or to have high blood pressure. And we call this the silent killer because usually high blood pressure comes with no symptoms whatsoever. In addition to being one type of cardiovascular disease, high blood pressure is also a risk factor for developing other heart problems such as heart attack, stroke, heart failure, kidney damage, and also blindness if it's uncontrolled.
Blood pressure is simply the measure of the force of blood pushing against the walls of the arteries as the blood travels through our circulatory system, and so there are two different types of blood pressure that you see: you see a systolic number over a diastolic number when you get your blood pressure. The systolic is the pressure when the heart contracts or beats, and the diastolic pressure is when the heart relaxes or is at rest.
On this slide you can see the categories or classifications for determining blood pressure levels in adults, and these, it's important to note, are based on two or more properly-measured blood pressure readings on two or more office visits, so we're talking about a sustained high level of blood pressure, not just a one-time reading, that should be used to classify someone as normal, pre-hypertensive or high blood pressure.
And there are both primary and secondary causes of high blood pressure, and primary causes accounts for about 90% to 95% of all cases, where we really don't know the specific cause of the high blood pressure but we do know some of the risk factors including older age, being overweight, a family history of hypertension and also chronic stress in someone's life, so repeated exposure to stress. In the secondary causes of high blood pressure, this is where the high blood pressure comes secondary to another disorder that causes the high blood pressure, and this accounts for just 5% to 10% of all cases. So most cases of high blood pressure we're not entirely sure what the cause is, but we do know some of the risk factors and some of the ways for controlling blood pressure.
Yet another type of cardiovascular disease is congestive heart failure. We also call this simply heart failure, and this is where your heart is too weak to pump blood effectively throughout the body, and so you might have a backup of fluids in the lungs, the legs, the arms, etc.—other parts of your body—and the development of congestive heart failure can result, slowly over time, from previous heart attacks, hypertension, could result from heart defects at birth, and many other reasons.
There are many different risk factors for cardiovascular disease, and over the final slides we'll talk about both modifiable and non-modifiable major risk factors for cardiovascular disease, and these are risk factors that have strong relationships or associations with the development of cardiovascular disease. At the very end of this lecture we'll also talk about contributing risk factors, and these are factors that play a role in development of cardiovascular disease, but they just don't have quite as strong of a relationship with this disease as the ones that we'll talk about that are listed here on this slide. So we'll start with the modifiable variables and we'll cover those in the next few slides.
The first entirely modifiable major risk factor for cardiovascular disease is cigarette smoking, and this is directly associated with about 20% of all deaths from cardiovascular disease. So why does smoking have such an impact on cardiovascular disease development? Well, we know that smoking can cause increased levels of your low density lipoproteins, or LDL cholesterols, and reduce high density lipoproteins, or good cholesterols, that contribute to a buildup up plaque in the arteries. We also know that nicotine, the stimulant in cigarette smoke, speeds up the heart rate and contributes too increased blood pressure. Carbon monoxide, the gas in cigarette smoke, reduces the amount of oxygen available to your heart and lungs and makes the heart work harder to pump blood throughout the body. But as we'll see in the next slide, the good news is that quitting smoking has almost immediate health benefits and decreases the risk of cardiovascular disease significantly.
Beginning just 20 minutes after your last cigarette, your body begins to restore itself to its healthy state, so after just 20 minutes your heart rate decreases, which is a good thing; it means your heart's not working quite as hard at rest. Just 12 hours later, the harmful carbon monoxide levels are no longer present in your body. Within a year it should be easier for you to be physically active because your coughing and your shortness of breath decrease. After just one year your risk of coronary heart disease is half that of a smokers, and after 15 years your risk of heart disease is the same as a non-smoker's risk. So clearly if you or someone else you know is smoking, it's worth your while to stop smoking or encourage others in your life to stop smoking, if for no other reason than the benefits on cardiovascular health.
The next major risk factor for developing cardiovascular disease is physical inactivity, and research shows a consistent inverse relationship between physical activity and the mortality rate from all types of cardiovascular disease, and so that means with more physical activity you see less death from cardiovascular disease; that's what the inverse relationship means. And so in Chapter 4 we talked about the strengthening of the heart with physical activity, and on this slide you can see some of the direct effects of physical activity on your heart muscle and your cardiovascular system. Maintaining your oxygen supply to the heart into the brain decreases the likelihood of development of plaque buildup in the arteries, or atherosclerosis. We already learned that participating in physical activity decreases your heart rate at rest which, again, reduces the workload on your heart, which is good. Physical activity also allows your heart to function better, so we see increased stroke volume at rest. Again, all these things are things we covered in Chapter 4, the benefits of participating in physical activity for your heart. And finally, another possible mechanism by which physical activity is directly related to decreased risk of cardiovascular disease is through increases in the electrical stability of the heart, helping your heart to maintain its normal rhythm.
But in addition to having direct effects on your cardiovascular system, physical activity also has indirect effects on your risk of cardiovascular disease by improving your blood lipid profile, so decreasing the LDL cholesterol, or the bad cholesterol, and increasing high density lipoproteins. Physical activity can also help with weight loss, which can have wide-ranging implications for decreasing the risk of cardiovascular disease. We, as we talked about in the last section, can see increase insulin sensitivity and a reduced risk of diabetes, which is another risk factor for cardiovascular disease. With physical activity we also see that stress is a contributing factor that can make other risk factors worse, so physical activity is helpful for controlling stress.
The third major risk factor for cardiovascular disease that we'll talk about that's modifiable are high levels of fat in the blood, both cholesterol and triglycerides, and if your levels of cholesterol are elevated, either from eating too much food containing cholesterol or from the rate at which the cholesterol is processed by the liver, it can begin to build up in the walls of the arteries like we talked about earlier in this lesson. And so, again, we want to eat less of those low density lipoproteins, or the bad cholesterols, and more of the good cholesterol, or high density lipoproteins. The other type of fat that can build up in your blood are called triglycerides, and these are also associated with the development of atherosclerosis.
Here are the guidelines for the total LDL and HDL cholesterol levels, and remember that you want your HDLs to be high, your LDLs to be low, and to get the best possible measure of your lipid profile, these tests should be conducted after fasting. And because you can't see or feel the buildup of fats in the blood, it's recommended that all healthy adults, even healthy adults, get tested once every five years for their blood lipid levels, and if you have more risk factors, then you probably want to get tested more frequently.
The next major risk factor for cardiovascular disease is high blood pressure, or hypertension, and remember that this is also a type of cardiovascular disease by itself, but in addition to that it's also a risk factor for developing many other types of cardiovascular disease, and we know that having hypertension accelerates the development of atherosclerosis, it makes your heart work harder, and it's one of the most preventable and treatable types of cardiovascular disease.
There are many different things that you can do to control your blood pressure. There are nine listed here on this slide, including losing weight, eating healthy foods and becoming more physically active.
The next major risk factor for cardiovascular disease is excess weight, in particular excess body fat that's concentrated around the midsection, or that visceral fat that we talked about in previous lectures, and being overweight or obese is associated with significant illness and mortality from cardiovascular disease. We also know that even with modest weight loss, as 5% to 10%, a person can have significant reductions in their risk of developing cardiovascular disease, so even small weight losses are important for improving risk for cardiovascular disease.
The final major modifiable risk for cardiovascular disease is diabetes mellitus, and specifically type II diabetes. And we talked about diabetes in the last section and learned that this group of diseases, marked by high blood glucose levels, puts people at a much higher risk of developing cardiovascular disease compared to people without diabetes.
On this slide you can see the contributing cardiovascular disease risk factors, and remember these are less strongly, but still related to the risk of developing cardiovascular disease. And the first one is stress, and stress is something that's present in everyone's life, but how we deal with it differs from person to person. There's a great deal that we still need to learn about stress and its relationship with cardiovascular disease, but it might increase blood pressure, and another way stress might contribute to cardiovascular disease is by increasing the likelihood of other negative health behaviors. So for example, when someone gets stressed, if they choose to smoke or be inactive or sedentary, that's how stress potentially could contribute to cardiovascular disease, and so there's still much we need to learn, but we do know that stress is a contributing risk factor. Similarly, alcohol use, and specifically too much alcohol use or excessive alcohol use, can increase blood pressure and potentially lead to obesity, both of which are major risk factors for cardiovascular disease. And finally, what we choose to eat also contributes to our risk of developing cardiovascular disease, so diets rich in fruits and vegetables may decrease our risk, whereas a diet high in saturated fat, cholesterol and sodium might increase our risk for developing cardiovascular disease.
This final slide shows the non-modifiable, or the factors that we cannot change that are major risk factors for cardiovascular disease, and the first of these is increasing age, or getting older. Most deaths from cardiovascular disease occur in those who are greater than 65 years old. We also know that males are more likely, at least before women go through menopause, to develop cardiovascular disease, and so we think that hormones might play a role, because as women age and go through menopause, their risk of cardiovascular disease becomes about the same as males, and so some people think that potentially estrogen has a protective effect over females until they lose their estrogen as they go through menopause. And finally, heredity and race, so if someone in your immediate family had heart disease—your parents, your siblings—that puts you at a greater risk, and also we know that African American and Mexican Americans, compared to Caucasian Americans, have higher risk of developing cardiovascular disease. So these are three things, unlike the other factors that we talked about, these three you don't have any control over changing these. We know we're going to age, we're born one biological sex or another, and we're born into a particular heredity and race, all of which we cannot change. But the good news is that we talked about many factors, many lifestyle factors that we can change to help reduce our risk of developing cardiovascular disease, which is a major killer of Americans, adult Americans, in the United States today.
