C H A P T E R 20

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C H A P T E R 20
CARDIOVASCULAR DISEASE AND PHYSICAL ACTIVITY
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Learning Objectives
w Find out the major causes of chronic diseases
in the United States and how a lack of physical
activity contributes to these conditions.
w Learn how atherosclerosis, hypertension, and
coronary artery disease (CAD) develop and at
what age they begin.
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Learning Objectives
w Learn what blood pressure changes result from
endurance exercise training in moderately
hypertensive individuals.
w Review the value of cardiac rehabilitation in
treating a person who has suffered a heart
attack.
w Find out if there is any risk of death
associated with endurance exercise training.
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Cardiovascular Diseases
w Affect nearly 62 million Americans (or 1 in 5)
each year
w Result in 1 million deaths (1 out of every 2.5
deaths)

• Cost individuals, government, and private
  industry over
• 350 billion annually

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LEADING CAUSES OF DEATH IN THE U.S. IN 2002
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CAUSES OF DEATH FROM CARDIOVASCULAR DISEASES
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DECLINE IN DEATHS, 1940 - 1990
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Factors Contributing to Decline in Deaths
w Better and earlier diagnosis
w Better emergency and medical care
w Improved drugs for specific treatment
w Improved public awareness
w Increased use of preventive measures, including
lifestyle changes (exercise, diet, stress
reduction, etc.)
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Forms of Cardiovascular Disease
Coronary artery disease (CAD)
Stoke
Hypertension
Congestive heart failure
Peripheral vascular disease
Valvular, rheumatic, and congenital heart disease
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Coronary Artery Disease
Atherosclerosisprogressive narrowing of arteries
due to build up of plaque
Coronary artery disease (CAD)atherosclerosis in
the coronary arteries
Ischemiadeficiency in blood and oxygen delivery
to heart caused by CAD
Myocardial infarction (MI)heart attack due to
ischemia and oxygen deprivation leading to muscle
cell death and necrosis
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Atherosclerosis
Atherosclerosis begins in childhood and
progresses at different rates, depending
primarily on heredity and lifestyle choices such
as smoking, diet practices, physical activity,
and stress.
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Normal vs. Atherosclerotic Artery
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AN ARTERY WALL
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DEVELOPMENT OF ATHEROSCLEROSIS
Thrombus ? Embolus
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Primary Risk Factors for CAD
Factors that can be controlled by lifestyle
changes
w Smoking
w Hypertension
w Physical inactivity
w Obesity
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Cholesterol
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 represent low risk.
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Secondary Risk Factors for CAD
Treatable
w Diabetes and high blood levels of insulin
Untreatable
w Family history of CAD
w Male sex
w Advanced age
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Hypertension
w Chronically elevated blood pressure
w Causes the heart to work harder against higher
afterload
w Is uncommon in childhood but can appear during
midadolescence
w Places strain on arteries causing them to
become less elastic over time arteriosclerosis
w Affects about one in every four adult Americans
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Classification of Blood Pressure for Adults, Age
18 Years and Older
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Controllable Risk Factors for Hypertension
w Insulin resistance (type II diabetes)
w Obesity
w Dietexcess sodium intake
w Use of oral contraceptives
w Physical inactivity
w Stress
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Uncontrollable Risk Factors for Hypertension
w Family history of hypertension
w Advanced age
w Race
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Syndrome X
It appears that hypertension, coronary artery
disease, abnormal blood lipids, type 2 diabetes,
and upper body obesity are linked through the
common pathway of insulin resistance and
hyperinsulinemia. Metabolic syndrome, syndrome X,
and civilization syndrome are terms used to
describe this interrelationship.
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Stroke
w Also called a cerebral vascular accident (CVA)
w Cerebral infarction refers to when blood flow
is blocked to one part of the brain due to a
blood clot (thrombus), embolus, or atherosclerosis
w Cerebral hemorrhage refers to a rupture of a
blood vessel that diminishes blood flow beyond
the rupture
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CEREBRAL INFARCTION AND HEMORRHAGE
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The Effects of Brain Damage Resulting From Stroke
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Congestive Heart Failure
w Heart muscle becomes too weak to produce
cardiac output to meet oxygen demands of the body
w Can result from damage to heart, hypertension,
atherosclerosis, and heart attack
w Blood backs up in veins causing edema,
particularly in the legs and ankles and the lungs
(pulmonary edema)
w Can progress to irreversible damage, thus
requiring a heart transplant
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KEY EXERCISE EPIDEMIOLOGISTS
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AMERICANS AT INCREASED CAD RISK
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REDUCTION OF RELATIVE RISK
Percentile of Activity Level
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Benefits of exercise
McArdle, Katch, and Katch, Exercise Physiology,
Williams Wilkins, 1996
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Physical Inactivity and CAD
Epidemiological evidence shows that physical
inactivity doubles the risk of CAD. Low-intensity
activity or moderate fitness is sufficient to
reduce the risk of this disease.
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Aerobic Training Adaptations
w Produces larger coronary arteries
w Increases heart size
w Increases heart pumping capacity
w Improves circulation of blood to heart through
increased collateral vessel formation
w Reduces blood pressure (afterload) in
individuals with moderate hypertension
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Left Main Coronary Arteries in Monkeys Fed
Atherogenic Diets
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How Exercise Reduces Risk of Disease
w Improves the hearts pumping capacity, work
capacity, and circulation
w Improves blood lipid profiles (?HDL-C ?total-C
and aLDL-C)
w Controls blood pressure, weight, and blood
glucose levels
w Controls weight, reduces body fat, and
increases muscle mass
w Alleviates stress and usually results in
decreased cigarette smoking
w Reduces insulin resistance
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Key Points
Risk of Death During Exercise
w 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.
w Deaths during exercise are rare.
w In people over 35 most deaths during exercise
are caused by a cardiac arrhythmia due to
atherosclerosis.
w Deaths during exercise in people under age 35
are usually caused by hypertrophic
cardiomyopathy, congenital conditions, aortic
aneurysm, or myocarditis.
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HEART ATTACK RISK AND EXERCISE