20

Cardiovascular Disease and Physical Activity

chapter

CARDIAC ADVANTAGES

• Blood Flow• Oxygen Uptake• Lactate Uptake• Autorhythmaticity

HEALTHY vs BLOCKED ARTERY

The Leading Causes of Death in the United States in 2003

Data from American Heart Association, 2006.

Factors Contributing toDecline in Deaths

• Better and earlier diagnosis• Better emergency and medical care• Improved drugs for specific treatment• Improved public awareness• Increased use of preventive measures, including

lifestyle changes

Cardiovascular Diseases

• Coronary artery disease (CAD)• Hypertension and stroke• Congestive heart failure• Peripheral vascular disease• Valvular, rheumatic, and congenital heart disease

The Leading Causes of Death From Cardiovascular Disease

Data from American Heart Association, 2006.

Coronary Artery Disease

Atherosclerosis is the progressive narrowing of arteries due to buildup of plaque.

Coronary artery disease (CAD) involves atherosclerosis in the coronary arteries.

Ischemia is a deficiency of blood to the heart caused by CAD.

Myocardial infarction is a heart attack due to ischemia.

Progressive Formation of Plaque in a Coronary Artery

Did You Know . . . ?

Atherosclerosis begins in infancy and progresses at different rates, depending primarily on heredity and lifestyle choices such as smoking history, diet practices, physical activity, and stress.

Classification of Blood Pressure for Adults Age 18 Years and Older

Normal <130 <85

High normal 130-139 85-89

Hypertension 140 90

Stage 1 (mild) 140-159 90-99

Stage 2 (moderate) 160-179 100-109

Systolic DiastolicCategory (mmHg) (mmHg)

Hypertension

• It is chronically elevated blood pressure.• It causes the heart to work harder.• It is uncommon in childhood but can appear during mid-

adolescence.• It places strain on arteries, causing them to become less

elastic over time.• It affects about 1 in every 4 adult Americans.

Stroke

• It is also called a cerebral vascular accident (CVA).• Cerebral infarction refers to when blood flow is blocked to

one part of the brain due to a blood clot or atherosclerosis.

• Cerebral hemorrhage refers to a rupture of a blood vessel that diminishes blood flow beyond the rupture.

CEREBRAL INFARCTION AND HEMORRHAGE

Infarction Hemorrhage

Congestive Heart Failure

• Heart muscle becomes too weak to meet oxygen demands of the body.

• It can result from damage to heart, hypertension, atherosclerosis, and heart attack.

• Blood backs up in veins, causing edema.• It can progress to irreversible damage, thus requiring a

heart transplant.

The Three Layers of an Artery Wall

Illustration of fissure or rupture of an unstable plaque in a coronary artery

Primary Risk Factors for CADThat Can Be Controlled

• Tobacco smoking• Hypertension• Abnormal blood lipids and lipoproteins• Physical inactivity

(continued)

Primary Risk Factors for CAD (continued)

• Obesity and overweight• Diabetes and insulin resistance

Did You Know . . . ?

The ratio of total cholesterol (Total-C) to high-density lipoprotein cholesterol (HDL-C) may be the most accurate lipid index of risk for CAD. Values of 5.0 and greater indicate increased risk, while values of 3.0 and lower indicate low risk.

Controllable Risk Factors for Hypertension

• Insulin resistance• Obesity and overweight• Diet (sodium, alcohol)• Use of tobacco products• Physical inactivity

Did You Know . . . ?

It appears that hypertension, coronary artery disease, obesity, and diabetes are linked through the common pathway of insulin resistance. Metabolic syndrome, syndrome x, and civilization syndrome are terms used to describe this interrelationship.

Percentages of the U.S. Population at Increased Risk for Coronary Artery

Disease Based on Primary Risk Factors

Reproduced from Caspersen, C.J.: Physical activity and coronary heart disease. Physicians Sportsmedicine 1987; 15(11): 43-44.

Did You Know . . . ?

Epidemiological evidence shows that physical inactivity doubles the risk of CAD. Low-intensity physical activity is sufficient to reduce the risk of this disease.

Aerobic Training Adaptations

• Produce larger coronary arteries• Increase heart size• Increase heart pumping capacity• Improve circulation of blood to vessels surrounding heart• Reduce blood pressure in individuals with moderate

hypertension

How Exercise Reduces Riskof Disease

• Improves the heart’s contractility, work capacity, and circulation

• Improves ratio of blood lipids• Controls and prevents moderate hypertension• Controls weight, reduces body fat, and increases muscle

mass• Alleviates stress and decreases cigarette smoking• Reduces insulin resistance

Comparison of the Left Main Coronary Artery in (a) Sedentary and (b) Exercising

Monkeys on Atherogenic Diets

Key Points

Risk of Death During Exercise• There is an increased risk of heart attack during

actual exercise; however, over a 24-hour period, those who exercise regularly have a reduced risk of heart attack.

• Deaths during exercise are rare.• In people over 35, most deaths during exercise are

caused by a cardiac arrhythmia due to atherosclerosis.

• Deaths during exercise in people under age 35 are usually caused by hypertrophic cardiomyopathy, congenital conditions, aortic aneurysm, or myocarditis.

Risk of Primary Cardiac Arrest During Vigorous Exercise and at Other Times

Throughout a 24 h Period

Data from D.S. Siscovick et al., 1984, "The incidence of primary cardiac arrest during vigorous exercise," New England Journal of Medicine 311: 874-877.