In the previous lesson you learned about infectious diseases such as the flu and cold. When you get the flu or catch a cold, you have an acute illness, or one that you get over within a relatively short time. Imagine, though, if those cold or flu symptoms never went away, and if the limitations they put on your activities never let up. In the following sections you’ll learn about common chronic diseases and what you can do now to avoid them.
Cardiovascular disease (CVD) refers to chronic diseases that affect the circulatory system. One in four Americans has one or more cardiovascular diseases, and these diseases contribute to 60 percent of all deaths in the nation. The most common cardiovascular diseases are discussed here; many other forms also exist.
Coronary Heart Disease
The most common form of CVD is coronary heart disease, in which the arteries in the heart become clogged or hardened. This is the leading cause of death in the United States. Clogged arteries, a condition called atherosclerosis (figure 2), can result from eating a high-fat diet, getting too little exercise, smoking, or being very overweight. Hardened (inflexible) arteries, a condition called arteriosclerosis, tend to occur as we age, but we can limit its effects by living a healthy lifestyle. Both of these cardiovascular diseases can decrease blood flow to the heart muscle, which can lead to chest pain known as angina and heart attacks. A heart attack is a cutting off of blood flow to a portion of the heart, which causes the cells in that area to die. Figure 3 shows how a blood clot or piece of plaque can break loose and block blood flow to the heart.
Figure 2 Plaque buildup in coronary heart disease.
Figure 3 A blood clot can cause a heart attack by preventing the heart from getting enough oxygenated blood.
Inadequate blood supply can also damage the brain. For example, atherosclerosis or a blood clot can block an artery that supplies the brain with blood and cause a stroke. This is the most common type of stroke, and it is called an ischemic stroke (inadequate blood supply). A stroke can also occur if a blood vessel in the brain bursts, causing severe bleeding; this type is known as a hemorrhagic stroke. Some strokes are severe enough to cause death, and many others result in disability. This is the fourth leading cause of death in the United States. A person has a disability when he or she is unable to perform activities or actions in the way they would normally be performed due to a restriction or impairment (see the Disability section later in this lesson for more information). After a stroke, many people have speech or movement disability due to the damage caused in the brain.
Peripheral Artery Disease
Atherosclerosis can also occur in arteries that take blood to parts of the body other than the heart, and this condition is called peripheral artery disease (PAD). It can compromise circulation to organs and limbs, resulting in symptoms that include leg pain, muscle aches, poor nail or hair growth, decreased temperature in one leg or arm, or sores and wounds on the toes that don’t heal properly. About eight million Americans have PAD. The risk of developing it increases with age, and it is more common among people who smoke or have diabetes, high blood pressure, or high cholesterol.
High Blood Pressure
Another form of CVD is high blood pressure, also known as hypertension. Each time your heart beats, it moves blood through your arteries at high speed and with a certain amount of force. The amount, or measure, of that force is your blood pressure. People with high blood pressure have higher than normal amounts of force in their arteries, which can damage artery walls as it pushes blood against them. High blood pressure is a risk factor for both coronary heart disease and stroke.
Monitoring blood pressure is a tool for reducing the risk of coronary heart disease and stroke.