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Cardiovascular Disease and Physical Activity. CHAPTER 21 Overview Forms of cardiovascular disease Understanding disease process Determining individual.

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Presentation on theme: "Cardiovascular Disease and Physical Activity. CHAPTER 21 Overview Forms of cardiovascular disease Understanding disease process Determining individual."— Presentation transcript:

1 Cardiovascular Disease and Physical Activity

2 CHAPTER 21 Overview Forms of cardiovascular disease Understanding disease process Determining individual risk Reducing risk through physical activity Risk of heart attack and death during exercise Exercise training and rehabilitating patients with heart disease

3 Introduction to Cardiovascular Disease Cardiovascular disease leading cause of serious illness and death in United States Affects over 80 million Americans Accounts for 1/3 of all US deaths annually Over $500 billion in annual costs

4 Figure 21.1

5 Introduction to Cardiovascular Disease In 2006 alone, in the United States –448,000 bypass surgeries –1,313,000 coronary angioplasties –2,200 heart transplants Death rate steadily declining since 1960s –Improved public awareness and lifestyle changes –Better and earlier diagnosis –Better treatment options A major health concern worldwide

6 Table 21.1

7 Forms of Cardiovascular Disease Coronary heart disease (CHD) Hypertension Stroke Heart failure Other (peripheral, valvular, congenital)

8 Forms of Cardiovascular Disease: Coronary Heart Disease Accounts for half of cardiovascular deaths Progressive narrowing of coronary arteries –Fatty plaque formation –Atherosclerosis –Blood supply to myocardium compromised –Myocardial ischemia  angina pectoris Leads to myocardial infarction (MI) –Heart attack –Irreversible heart muscle cell death due to lack of O 2

9 Figure 21.2

10 Forms of Cardiovascular Disease: Coronary Heart Disease Atherosclerosis begins early in life –Fatty streaks appear in infancy, childhood –Fatty streaks appear in coronary arteries in teens –Fibrous plaques develop in 20s –Combination of genetics and lifestyle

11 Forms of Cardiovascular Disease: Hypertension High blood pressure –Systolic ≥140 mmHg, diastolic ≥90 mmHg –Affects 32% of US adult population Heart must work harder to eject blood Places greater strain on arteries Causes enlarged heart, scarred/stiff arteries Eventually leads to atherosclerosis, MI, etc.

12 Forms of Cardiovascular Disease: Hypertension Prehypertension –Systolic 120 to 139 mmHg –Diastolic 80 to 89 mmHg –Affects 28% of US adult population More common in black Americans –1.8 times greater rate of fatal stroke –1.5 times greater rate of heart disease death –4.2 times greater rate of kidney disease

13 Table 21.2

14 Forms of Cardiovascular Disease: Stroke Affects cerebral arteries –Restricts brain blood flow –795,000 strokes in United States annually Ischemic stroke –Most common type –Obstructed cerebral artery limits O 2 delivery –Cerebral thrombosis –Cerebral embolism

15 Forms of Cardiovascular Disease: Stroke Hemorrhagic stroke –Intracerebral hemorrhage –Subarachnoid hemorrhage –Vessel in or on brain ruptures –Arises from aneurysms (secondary to hypertension or atherosclerotic damage) Rupture  ischemia and pressure on brain tissue  death of brain tissue

16 Forms of Cardiovascular Disease: Stroke Effect of stroke depends on region affected –Paralysis on one side most common –Each side of brain controls opposite side of body Strokes in right brain –Vision problems, memory loss –Quick, inquisitive behavior Strokes in left brain –Speech/language problems, memory loss –Slow, cautious behavior

17 Forms of Cardiovascular Disease: Heart Failure Chronic, progressive weakening of the heart –Too weak to maintain cardiac output –Results from damage to and overworking of heart –Hypertension major contributor (75% of cases) –Other causes: atherosclerosis, valve diseases, viral infection, MI Causes edema, pulmonary edema Ultimately requires heart transplant

18 Forms of Cardiovascular Disease: Other Cardiovascular Diseases Peripheral vascular diseases –Arteriosclerosis (obliterans) –Varicose veins, phlebitis Valvular diseases –Often from viral infections –Rheumatic heart disease Congenital heart disease –Congenital defects –Can affect aorta, valve, or septum

19 Understanding the Disease Process: Coronary Heart Disease Pathology of CHD affects vessel wall –Tunica intima: endothelium –Tunica media: smooth muscle cells, elastin –Tunica adventitia: collagen Early theory: initial injury to endothelium –Platelets, monocytes adhere to injury (PDGF) –Smooth muscle cells and lipids migrate to intima –Collection of debris in intima  plaque

20 Figure 21.4

21 Figure 21.5

22 Understanding the Disease Process: Coronary Heart Disease Recent theory: monocytes attach between endothelial cells –Become macrophages –Ingest oxidized LDL-C –Become large foam cells, form fatty streaks Endothelial cells slough off –Expose underlying connective tissue –Allows platelets to attach –Endothelial injury not always precipitating event

23 Understanding the Disease Process: Coronary Heart Disease Endothelial injury or disruption comes from –High blood LDL –Free radicals from cigarette smoke –Hypertension –High plasma homocysteine –Infectious microorganisms Atherosclerosis now considered to be inflammatory disease

24 Understanding the Disease Process: Coronary Heart Disease Plaque consists of –Smooth muscle, inflammatory cells, lipids –Fibrous cap (thick or thin) –Thin caps = more unstable = easier rupture –Rupture  thrombus formation Rupture and thrombus account for 70% of MIs Plaques are dynamic (erode, repair, grow)

25 Figure 21.6

26 Understanding the Disease Process: Hypertension Poorly understood condition 90 to 95% of cases idiopathic Remaining 5 to 10% secondary to other issues –Kidney disease –Adrenal tumors –Congenital defect of aorta

27 Determining Individual Risk Epidemiology of CHD and hypertension reveals relationships among disease factors –Large-scale public studies, often longitudinal –Framingham Heart Study Epidemiology does not define causal mechanisms of cardiovascular disease Epidemiology does provide researchers with valuable insights into disease risk factors

28 Determining Individual Risk: Coronary Heart Disease Uncontrollable CHD risk factors –Heredity, family history –Race –Sex (male > female) –Age Must try to mitigate risk via controllable CHD risk factors instead

29 Determining Individual Risk: Coronary Heart Disease Controllable CHD primary risk factors –Tobacco smoke –Hypertension –Abnormal blood lipid profile –Physical inactivity –Obesity, overweight –Diabetes, insulin resistance As number of risk factors , risk of CHD 

30 Determining Individual Risk: Coronary Heart Disease Other putative CHD risk factors –C-reactive protein (CRP) –Fibrinogen –Homocysteine –Lipoprotein(a) Inflammatory processes and markers may be involved in risk

31 Table 21.3

32 Determining Individual Risk: Coronary Heart Disease Blood triglycerides Blood cholesterol Lipoproteins –VLDL cholesterol (risk factor) –LDL cholesterol (risk factor) –HDL cholesterol (beneficial) Ratio of total cholesterol to HDL (best index)

33 Determining Individual Risk: Early Detection of CHD Risk Factors Early detection  preventive treatment In boys 8 to 12, girls 13 to 15 years old –19.8% had total cholesterol >200 mg/dL –5.2% had abnormal resting ECGs –37.5% had 20+ percent body fat High risk in childhood  high risk as adult

34 Determining Individual Risk: Hypertension Uncontrollable risks similar to those for CHD Controllable risk factors for hypertension –Insulin resistance –Obesity, overweight –Diet (sodium, alcohol) –Tobacco use –Oral contraceptives –Stress –Physical inactivity

35 Determining Individual Risk: Metabolic Syndrome Metabolic syndrome –Also called insulin resistance syndrome –Links CHD, hypertension, abnormal blood lipids, type II diabetes, and abdominal obesity to insulin resistance and hyperinsulinemia –Series of correlations and associations Possible causes –Obesity and insulin resistance trigger cascade of events –Systemic inflammation

36 Reducing Coronary Heart Disease Risk Through Physical Activity Epidemiological evidence –Risk of MI 2 to 3 times higher in sedentary populations –Both occupational and leisure activity –Similar results for both men and women CDC findings –Physical inactivity equal to other risk factors –Sedentary lifestyle 3 times more common than other major risk factors (smoke, hypertension, cholesterol)

37 Reducing Coronary Heart Disease Risk Through Physical Activity How much physical activity  risk of CHD? –Physical activity versus physical fitness –Physical activity more important than fitness Walking and gardening—examples of low- impact, low-level activity   risk More vigorous exercise may yield greater benefits

38 Reducing Coronary Heart Disease Risk Through Physical Activity Exercise type and intensity related to CHD risk –Run 6 mph for 1 h per week  42%  risk –Weight train 30 min per week  23%  risk –Brisk walk 30 min per day  18%  risk –Swimming and cycling unrelated to risk Higher intensity  greater risk reduction

39 Reducing Coronary Heart Disease Risk Through Physical Activity Physical fitness and physical activity may be independent risk factors for CHD –Higher fitness and activity both reduce risk –Fitness more potent than activity Controversial findings, merit more research

40 Reducing Coronary Heart Disease Risk Through Physical Activity

41 Physiological adaptations to exercise that may reduce risk –  Contractility via LV hypertrophy –  Diameter and capacity of coronary vessels –  Endothelial function and vasodilation –  Vascular inflammation Exercise  enhanced cardiac and vascular function (even with atherogenic diet)

42 Reducing Coronary Heart Disease Risk Through Physical Activity Exercise  reduced risk factors –  Blood pressure (systolic, diastolic) –  LDL, total cholesterol –  HDL cholesterol –  Blood triglycerides –  Total cholesterol relative to HDL Exercise exerts biggest effect on blood lipid profile risk factors

43 Reducing Coronary Heart Disease Risk Through Physical Activity Effect of exercise on other risk factors –Weight control –Diabetes management –Stress reduction –Anxiety reduction Note: effects of exercise on blood-related risk factors also reflect exercise effects on plasma volume and body weight

44 Reducing Hypertension Risk Through Physical Activity Effect of exercise on hypertension not as well established as effects on CHD Epidemiological evidence – More active people in studies had lower systolic and diastolic pressures –Highly fit individuals less prone to hypertension –Hypertension associated with low fitness

45 Reducing Hypertension Risk Through Physical Activity Physiological adaptations to exercise –  Plasma volume (does not  blood pressure) –  In overall sympathetic nervous activity –  Vasodilation and vascular remodeling Physiological mechanisms that lower blood pressure still poorly understood

46 Reducing Hypertension Risk Through Physical Activity Exercise  reduced risk factors –  Body fat –  Blood glucose levels –  Insulin resistance  BP unrelated to duration of training  BP may be greater with low or moderate intensity

47 Risk of Heart Attack and Death During Exercise Infrequent but highly publicized Risk very, very low –Men: 1 death per 1.42 million h of exercise –Women: 1 death per 36.5 million h of exercise Habitual exercise   risk of death When death occurs, age affects cause –Under 35: more often genetic abnormalities, aneurysm –Over 35: more often arrhythmia caused by CHD

48 Figure 21.8

49 Risk of Heart Attack and Death During Exercise CPR outside of hospital increases survival of cardiac arrest by 2 to 3 times Bystanders rarely perform CPR –Fear of doing it wrong –Fear of legal liability –Fear of infection from rescue breathing Chest compressions without breathing  better survival outcomes than traditional CPR

50 Exercise and Rehabilitating Patients With Heart Disease Endurance training  changes that reduce work, O 2 demand of heart Aerobic exercise helps prevent future complications –  Capillary:muscle fiber ratio –  Plasma volume –  Or maintain O 2 supply to heart –  Blood flow to heart –  LV function (continued)

51 Exercise and Rehabilitating Patients With Heart Disease (continued) Aerobic exercise helps prevent future complications –  Blood pressure –  Blood lipid values –  Body fat –  Glucose control –  Stress Combining resistance training and aerobic exercise optimal

52 Exercise Training and Rehabilitating Patients With Heart Disease Comprehensive program consists of –Exercise, physical activity –Counseling (nutritional, psychological, sexual) –Support forums Exercise rehabilitation improves outcomes –20% lower total mortality and 26% lower risk of death from subsequent MI Rehabilitation patients should have medical evaluation, GXT, exercise prescription

53 Table 21.4


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