CARDIOVASCULAR DISEASE AND PHYSICAL ACTIVITY CARDIOVASCULAR DISEASE AND PHYSICAL ACTIVITY C HAPTER 20 C HAPTER 20
Learning Objectives Find out the major causes of chronic diseases in the United States and how a lack of physical activity contributes to these conditions. Learn how atherosclerosis, hypertension, and coronary artery disease (CAD) develop and at what age they begin. Discover what specific physiological alterations that result from exercise training reduce the risk of death from CAD, hypertension, and heart disease. (continued)
Learning Objectives Learn what blood pressure changes result from endurance exercise training in moderately hypertensive individuals. Review the value of cardiac rehabilitation in treating a person who has suffered a heart attack. Find out if there is any risk of death with endurance exercise training.
Factors Contributing to Decline 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
Coronary Artery Disease Atherosclerosis —progressive narrowing of arteries due to build up of plaque Coronary artery disease (CAD) —atherosclerosis in the coronary arteries Ischemia —deficiency in blood to heart caused by CAD Myocardial infarction —heart attack due to ischemia
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 Stage 3 (severe) 180-209 110-119 Stage 4 (very severe) 210 120 Systolic Diastolic Category (mmHg) (mmHg)
Hypertension Is chronically elevated blood pressure Causes the heart to work harder Is uncommon in childhood but can appear during midadolescence Places strain on arteries causing them to become less elastic over time Affects about one in every four adult Americans
Stroke 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.
Congestive Heart Failure Heart muscle becomes too weak to meets oxygen demands of the body Can result from damage to heart, hypertension, atherosclerosis, and heart attack Blood backs up in veins causing edema Can progress to irreversible damage, thus requiring a heart transplant
Secondary Risk Factors of CAD Obesity Diabetes and high blood levels of insulin Family history of CAD Male gender Advanced age
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 represent low risk.
Controllable Risk Factors for Hypertension Insulin resistance Obesity Diet Use of oral contraceptives Physical inactivity
Uncontrollable Risk Factors for Hypertension Family history of hypertension Advanced age Race
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.
Did You Know…? Epidemiological evidence shows that physical inactivity doubles the risk of CAD. Low-intensity activity is sufficient to reduce the risk of this disease.
Aerobic Training Adaptations Produces larger coronary arteries Increases heart size Increases heart pumping capacity Improves circulation of blood to vessels surrounding heart Reduces 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 Reduces insulin resistance Alleviates stress and decreases cigarette smoking
Key Points 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. Risk of Death During Exercise 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.