Cardiovascular Disease

Cardiovascular Disease

• The number one cause of death in the United States

• Caused the death of over 900,000 Americans each year

• Economic cost of over $351 billion dollars

• Since 1960, a gradual decline in morbidity and mortality due to cardiovascular disease

The Leading Causes of DeathFrom Cardiovascular Disease

Data from American Heart Association, 2006.

Factors Contributingto Decline in Deaths

• Improved public awareness (e.g., concept of risk factors)

• Increased use of preventive measures, including lifestyle changes

• Better and earlier diagnosis• Improved drugs for specific treatment• Better emergency and medical care

Your risk for developing cardiovascular disease is reduced when you don’t smoke, get regular exercise, eat well, maintain a healthy body weight, and manage stress.

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Anatomy and Function of the Cardiovascular System

Cardiovascular Diseases

• Coronary artery disease (CAD)(CHD)heart• Hypertension • Stroke• Heart failure• Peripheral vascular disease• Valvular, rheumatic, and congenital heart disease

Heart Attack

• Coronary thrombosis or myocardial infarction

• Lack of blood flow or supply to areas of the heart

Coronary Artery Disease

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

Atherosclerosis: progressive narrowing of the arteries due to plaque formation

Ischemia: a deficiency of blood flow to the heart caused by CAD

Angina pectoris: chest pain

Myocardial infarction: a heart attack due to ischemia leading to irreversible damage and necrosis

Blood Flow Blockage in the Coronary Arteries

Warning signs of a heart attack include uncomfortable pressure or pain in the center of the chest that lasts 2 minutes or longer; pain that spreads to the shoulders, neck or arms; or severe pain, dizziness, fainting, sweating, nausea, or shortness of breath. If you experience any of these signs, you should seek medical help immediately.

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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.

Atheresclerosis

Angina Pectoris

• Chest pain

• Lack of blood flow and oxygen to areas of the heart

• Increased risk of heart attack

Other Types of Cardiovascular Disease

• Congenital heart defects—abnormal heart structures, vessels, and valves at time of birth• Rheumatic heart disease—bacterial infection of the heart that damages heart valves• Congestive heart failure—condition that occurs when other diseases have damaged the heart and limited its function

(continued)

Other Types of Cardiovascular Disease

• Bacterial endocarditis—infection of the lining or valves of the heart

• Aneurysms—a weakness or bulge in an artery that can burst and lead to massive internal bleeding(動脈瘤 )

Major alterable Major unalterable Contributing Hypertension Age Stress

Tobacco smoking Genetics Excessive alcohol

Cholesterol Gender

Physical inactivity

Obesity

Diabetes

Risk Factors for CHD

Major Unalterable Risk Factors for CHD

• Heredity—family history and race

• Gender—males are at higher risk

• Age—increased age relates to increased risk

Hypertension

• About one in every three adult Americans has hypertension

• Causes the heart to work harder• Strains the systemic arteries and arterioles• Can lead to atherosclerosis, heart attacks, heart failure,

stroke, and renal failure

Reducing the Risk of Hypertension Through Exercise

• People who are active and those who are fit have reduced risk for developing hypertension

• Resting blood pressure decreases by training in people with hypertension(aerobic and endurance ex)

Controllable Risk Factorsfor Hypertension

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

Pathophysiology of Hypertension

More than 90% of people with hypertension have essential hypertensionRisk factors – Heredity, including race – Increasing age and male sex– Sodium sensitivity– Excessive alcohol consumption and use of tobacco

products– Obesity and overweight– Diabetes or insulin resistance– Physical inactivity– Oral contraceptives– Pregnancy– Stress

High Blood Cholesterol

• Cholesterol is a fatlike substance found in the body’s cells and bloodstream.

• The body produces cholesterol primarily through the liver; we also consume cholesterol through our diet.

• Two types relevant to CHD are high density lipoprotein (HDL-C) and low density lipoprotein (LDL-C).

• HDL-C decreases the risk of CHD.• LDL-C increases the risk of CHD.

Americans with High Cholesterol

Standards for Cholesterol

Desirable: less than 200mg/dlBorderline high: between 200 and 239mg/dlHigh: 240mg\dl or higher

Total Cholesterol (TC)

Optimal: less than 100mg/dlBorderline high: between 130 and 159mg/dlHigh: between 160mg/dl and 189mg/dl

LDL-C

Low: less than 40mg/dlHDL-C

The Cholesterol Ratio

Cholesterol ration = TC ÷ HDL - C

Example: TC = 140, HDL - C = 40

Cholesterol Ratio = 180 ÷ 40 = 4.5

The American Heart Association recommends a cholesterol ratio of less than 3.5.

The Cholesterol Ratio and Risk of CHD

Your total cholesterol level should be below 200 milligrams per deciliter of blood. Your LDL-C count should be less than 130 milligrams per deciliter. It’s desirable that your ratio of total cholesterol to HDL-C be 3.5 or less.

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Other Major Risk Factors for CHD

• Smoking—doubles the risk for CHD

• Diabetes—inability to control blood levels increases the risk of CHD

• Obesity—related to many health problems and greatly increases the risk of CHD

Physical Inactivity: A Major Risk Factor for CHD

• In 1992, the American Heart Association classified physical inactivity as a major risk factor for CHD.

• Low levels of physical activity and cardiorespiratory fitness can double the risk of CHD.

There are a number of CHD risk factors that you can control: high blood pressure, high blood cholesterol, elevated triglycerides, smoking, diabetes, excessive fat, and physical inactivity. Inactive people are twice as likely as active people to die from cardiovascular disease.

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Contributing Risk Factors for CHD

• Excessive and prolonged stress can increase the risk of CHD.

• Personality traits of anger and hostility can increase the risk of CHD

• Excessive use of alcohol

Epidemiological Evidence

• Physical inactivity doubles the risk of CAD• Low-intensity physical activity is sufficient to reduce the

risk of this disease• Health benefits do not require high-intensity exercise• More vigorous exercise likely provides even greater

benefits

Physical Activity vs. Physical FitnessDose–Response Curve

Reprinted, by permission, from P.T. Williams, 2001, "Physical fitness and activity as separate heart disease risk factors: A metaanalysis," Medicine and Science in Sports and Exercise 33: 754-761.

Aerobic Training Adaptations

• Produce larger coronary arteries which increases the capacity for blood flow to the heart

• Increased cardiac pumping capacity• Improved collateral circulation in the heart• Improved endothelial function• Reduce blood pressure (~7 mmHg) in individuals with

mild to moderate hypertension• Improves cholesterol ratio• Weight reduction• Improves insulin sensitivity• Stress management

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

Monkeys on Atherogenic Diets

Stroke: Brain Attack

• Cerebral thrombosis—blockage of blood flow to the brain.

• Cerebral hemorrhage—bursting of an aneurysm or a blow to the head that cause bleeding into the cranium.

The severity of a stroke relates to the amount of brain tissue affected.

Risk Factors for Stroke

Unalterable

• Heredity—Family history and race. African-Americans have a much higher risk of stroke than white Americans do.

• Gender—Males have a higher risk than females.

• Age—As age increases the risk of stroke increases.

Risk Factors for Stroke

Alterable

• Hypertension—The major risk factor for stroke.

• Smoking

• History of transient ischemic attacks (ministrokes)

• High red blood cell counts

Risk Factors for Stroke

Contributing

• High blood cholesterol and triglycerides

• Physical inactivity

• Obesity