chapter
20
Cardiovascular
Disease and
Physical Activity
CARDIAC ADVANTAGES
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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 to
Decline in Deaths
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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
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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
Category
Normal
Systolic
(mmHg)
Diastolic
(mmHg)
<130
<85
130-139
85-89
140
90
Stage 1 (mild)
140-159
90-99
Stage 2 (moderate)
160-179
100-109
High normal
Hypertension
Hypertension
• It is chronically elevated blood pressure.
• It causes the heart to work harder.
• It is uncommon in childhood but can appear during midadolescence.
• 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 CAD
That Can Be Controlled
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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
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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
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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 Risk
of 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.