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Chapter 10 Cardiovascular Disease The heart and its blood vessels can become diseased, a common health problem called cardiovascular disease (CVD). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 300 297 Disease of Heart 250 Cancer Stroke 239 197 200 163 150 100 57 55 50 0 Men Figure 10.2 (adapted by gender) Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Women Atherosclerosis Most CVD is caused by deposits of material, often called plaque, that block the coronary arteries and the arteries that supply blood to the brain. These plaque deposits of cholesterol, fatty material, calcium, and other substances are called atherosclerosis. Fig. 10.3 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. CVD: Starts in Childhood Atherosclerosis often begins during childhood and progresses from fatty streaks in the arteries to raised deposits within several decades. About three in four elderly Americans have plaque deposits in their coronary and brain arteries, a process that began early in life because of inactivity, high-fat diets, low fruit and vegetable intake, and excess weight gain. Fig. 10.4 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 3 types of CVD Cerebrovascular disease (stroke) Coronary heart disease CHD) Peripheral artery disease PAD) Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Coronary Heart Disease Over time, atherosclerosis narrows the coronary arteries, reducing the flow of oxygen-rich blood. This is called coronary heart disease (CHD). One of every five deaths in the United States is from CHD, the most common form of CVD. Often, a blood clot forms in the narrowed coronary artery, blocking the blood flow to this part of the heart. This causes a heart attack, or what doctors call a myocardial infarction (MI). See Box 10.2 for warning signals of a heart attack. Each year, more than one million Americans have a heart attack, and about one-third of them will die. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. What is Stroke? Stroke is the common name for several disorders that occur within seconds or minutes after the blood supply to the brain is disturbed. The medical term is cerebrovascular disease or accident (CVA). The brain cannot store energy, and if deprived of blood for more than a few minutes, brain cells die from energy loss and certain chemical interactions that are set in motion. The functions these brain cells control—speech, vision, muscle movement, comprehension—die with them. Fig. 10.6 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Stroke Morbidity and Mortality About 700,000 Americans suffer a new or recurrent stroke each year. See Figure 10.9 for signs of stroke. About 1 in 4 people who have a stroke die within a year, 5 in 10 within 8 years. Each year, stroke kills about 160,000 people, accounting for one of every 15 U.S. deaths. Deaths rates are falling (see Figure 10.8). It's the third largest cause of death, ranking behind diseases of the heart and cancer. Of those who survive, 15-30% suffer long-term disabilities, needing help caring for themselves or when walking. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Types of Strokes About 10% of strokes are preceded by TIAs. Most strokes occur because of atherosclerosis. Clots that form in the area of the narrowed brain blood vessels (thrombus) or ones that float in (embolus) can then totally block the blood flow, causing the stroke. Other strokes occur when a blood vessel ruptures and bleeds (hemorrhagic stroke), often in a brain artery that has been weakened from atherosclerosis or HBP. Fig. 10.7 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Figure 10.8 600 500 Heart Disease ( 60%) 400 300 200 Stroke (72% decrease) 100 0 1950 1960 1970 1980 1990 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 2000 Current Risk Factors for Stroke Non-modifiable risk factors Age, male sex,ethnicity (African American), and family history of stroke. Well-documented modifiable risk factors High blood pressure Cigarette smoking Hyperlipidemia/dyslipidemia Diabetes mellitus Heart disease Sickle cell disease Carotid artery disease Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Stroke Risk Factor (cont) Less Well-Documented/Potentially Modifiable Risk Factors Obesity Physical inactivity Poor diet/nutrition Alcohol abuse High blood homocysteine Drug abuse Hypercoagulability (clots) Inflammatory processes Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Stroke Prevention (Table 10.4) To prevent stroke, follow these lifestyle habits Lose weight if overweight Reduce sodium intake to less than 2,400 mg per day Maintain adequate dietary potassium intake (fruits and vegetables) Limit alcohol intake Exercise regularly Avoid cigarette smoking and illicit drug use Eat a diet low in saturated fats and cholesterol, and high in whole grains, fruits, and vegetables Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Table 10.2 Risk Factors for Heart Disease According to the American Heart Association (Note: see Figure10.12 for CHD effect in lowering risk factors). Major Risk Factors That Can’t Be Changed 1. Heredity 2. Male 3. Increasing age % Adults With Risk Factor ------13% (over age 65) Major Risk Factors That Can Be Changed 1. Cigarette/tobacco smoke 2. High blood pressure 3. High blood cholesterol 4. Physical inactivity 5. Obesity 6. Diabetes 22% 26% (≥140/90 mm Hg) 17% (≥240 mg/dl) 39% 31% (BMI ≥30 kg/m2) 6.7% Contributing Factor 1. Individual response to stress ---- Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. ATP III Major Risk Factors (Exclusive of LDL Cholesterol) Cigarette smoking Hypertension (BP ≥140/90 mmHg or on antihypertensive medication) Low HDL cholesterol (<40 mg/dL)† Family history of premature CHD CHD in male first degree relative <55 years CHD in female first degree relative <65 years Age (men ≥45 years; women ≥55 years) † HDL-C 60 mg/dL counts as a “negative” risk factor; removes 1 risk factor from the total count. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Other ATP III Risk Factors* Life-Habit Risk Factors Obesity (BMI 30) Physical inactivity Atherogenic diet Emerging Risk Factors Lipoprotein (a) Homocysteine Prothrombotic factors Proinflammatory factors Impaired fasting glucose Subclinical atherosclerosis * In ATP III, diabetes is regarded as a CHD risk equivalent (risk for major coronary events = established CHD). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. ATP III: The Metabolic Syndrome as a Secondary Target of Therapy General Features of the Metabolic Syndrome Abdominal obesity Atherogenic dyslipidemia Elevated triglycerides Small LDL particles Low HDL cholesterol Raised blood pressure Insulin resistance (± glucose intolerance) Prothrombotic state Proinflammatory state Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Treatment of CHD When a coronary artery gets blocked, the heart muscle doesn't die instantly. If a victim gets to an emergency room fast enough, clot-dissolving agents can be injected to dissolve a clot in a coronary artery and restore some blood flow. These drugs must be used within a few hours of a heart attack for best effect. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Percutaneous transluminal coronary angioplasty (PTCA) Before performing this procedure, a doctor must find the blocked part of the coronary artery. A thin plastic tube called a catheter is guided through an artery in the arm or leg and into the coronary artery, and a liquid dye visible in X- rays is injected. A balloon is inflated at the arterial blockage to compress the plaque. Figure 10.13 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Figure 10.13 Often, a stent is left in the artery to prevent reclosing (a common complication) Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Coronary Artery Bypass Graft Surgery In coronary artery bypass graft surgery, surgeons take a blood vessel from another part of the body and construct a detour around the blocked area of the coronary artery. One end of the vessel is attached above the blockage; the other, to the coronary artery just beyond the blocked area. This restores blood supply to the heart muscle. Figure 10.13 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. An EKG can detect atherosclerosis buildup in the coronary arteries. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Cigarette Smoking Cigarette smoking is the leading underlying cause of death in the United States. Nearly 1 of every 5 deaths is the result of cigarette smoking, with ~435,000 smokers dying/yr from heart disease, cancer, and other diseases. An additional 9 million American smokers suffer from various debilitating diseases including bronchitis, emphysema, ulcers, and "hardening of the arteries." The decision not to smoke adds an average of 15 years of life when compared to the shortened life expectancy of those electing to smoke. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Figure 10.14 Tobacco Alcohol Toxic agents Sexual behavior Drug abuse 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 , 0, 0, 0, 0, 0, 0, 0, 0, 0, 50 0 5 0 5 0 5 0 5 0 1 1 2 2 3 3 4 4 5 Estimated number of deaths Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Figure 10.15 Lung cancer 123,000 Coronary heart disease 98,000 Other cancers 32,000 Chronic lung disease 72,000 Stroke 24,000 Other diagnoses 81,000 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Smoking Prevalence About 22% of U.S. adults smoke cigarettes, with rates higher among blue- collar workers, those with little education, and various minority groups. By 2010, U.S. health agencies hope to reduce tobacco use to 12% of adults. See Fig. 10.17 for gender comparison. Public attitudes toward smoking have changed, much of it due to the recent evidence that many adverse health effects are related to passive smoking (breathing someone else's cigarette smoke). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Table 10.5 % adults 18 years and older who smoke cigarettes. Group All adults Race/Ethnicity American Indian or Alaska Native Black or African American White Hispanic Asian Poverty level Below poverty level At or above poverty level Education Less than high school education High school graduate College degree Graduate degree Age group (yrs) 18 to 24 25-44 45 to 64 65 and older Males 25 Females 20 41 27 26 23 19 41 19 22 11 7 37 25 30 20 32 30 14 8 24 22 11 6 32 29 25 10 25 23 21 9 Cigarette Smoking Is Addictive Cigarette smoking almost always begins in the adolescent years. About 6,000 young people try a cigarette each day, with half becoming daily smokers. The prevalence of tobacco use among adolescents increased during the 1990s, but has since declined to 22%, just 6% above the 2010 goal of 16% (Figs. 10.18, 10.20). The mean number of cigarettes smoked daily per smokes if 20. Per capita consumption has dropped sharply since the 1960s (Fig. 10.19) (social influences and legislation). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Smoking Cessation Dependence on tobacco is a chronic condition that typically requires several attempts to quit successfully. Use economic (e.g., optimal level of taxes), regulatory (e.g., smoke-free sites), and comprehensive approaches. Educational strategies combined with community- and media-based activities can postpone/prevent smoking in 20-40% of adolescents. Every patient who uses tobacco should be offered treatment by an MD. Use of drugs (e.g., nicotine gum and patches) with behavioral approaches will enable 20-25% to remain smoke-free for at least one year. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Smoking Cessation, Weight Gain, Exercise Smokers who fail to quit often fear weight gain. The average smoker weighs about 7 lbs less. People who start smoking lose weight, while those who quit gain, with women adding on an average of 8 lbs and men 6 lbs. Major weight gain (more than 28 lbs) can be expected in 10% of men and 13% of women who quit smoking. Smoking elevates the RMR by 6-10% (about 200 calories), and when people quit, the rate falls back down. Food intake, especially of sweet foods, increases after quitting, resulting in 200-250 extra calories a day. In general, for most people who quit smoking: Weight gain is modest, and can be negated through prudent diet and exercise habits. Some evidence that smoking helps people stop smoking. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Hypertension Blood is carried from the heart to all of the body's tissues and organs in vessels called arteries. Blood pressure is the force of the blood pushing against the walls of those arteries. The heart beats about 60-75 times/minute, and the BP is at its greatest when the heart contracts, pumping blood into the arteries. This is called systolic BP. When the heart is resting briefly between beats, the BP falls, and is termed diastolic BP. Both BPs are important, and are usually presented together, such as 120/80 mm Hg, with the first number representing the systolic, and the second number, the diastolic BP. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Hypertension and Health High blood pressure usually doesn't give early warning signs, and for this reason is known as the "silent killer." High blood pressure increases the risk for coronary heart disease and other forms of heart disease, stroke, and kidney failure (see Figures 10.26 and 10.27). Starting at 115/75 mmHg, CVD risk doubles with each increment of 20/10 mmHg throughout the BP range. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Web site www.nhlbi.nih.gov/ Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Blood Pressure Classification According to the National High Blood Pressure Education Program, blood pressures can be categorized as follows: Systolic* Diastolic* Normal less than 120 less than 80 Prehypertension 120-139 80-89 Stage 1 hypertension 140-159 90-99 Stage 2 hypertension 160 100 *(mm Hg) Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Prevalence of Hypertension About 26% of adults have high blood pressure (HBP), a proportion that rises strongly to 2 in 3 among the elderly (see Figure 10.25). 65 million adults have HBP. 31% have prehypertension. Year 2010 target for HBP prevalence is 16% (Figure 10.10). In societies where salt and alcohol intakes are high, potassium intake from fruits and vegetables is low, and physical inactivity and obesity are the norm, HBP is common. Inactive and unfit individuals have a 20%-50% increased risk of developing HBP compared to their more physically active peers. Risk of HBP is high among African Americans, people with a family history of HBP, and the elderly. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Figure 10.25 Percent hypertensive 90 80 70 60 50 40 30 20 10 0 Males Females 82.8 72.5 68.4 58.9 53.9 44.9 30.9 31.7 17.1 15.1 8.1 2.7 20-35 35-44 45-54 55-64 Age in years Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 65-74 75+ Treatment of Hypertension Lifestyle modification is useful for prevention of HBP and treatment of prehypertension. Those with stage 1 and 2 hypertension should combine lifestyle modification with drug therapy. Review Table 10.7. See Table 10.6 for antihypertensive drugs. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Table 10.7 Classification and Management of BP for Adults Initial drug therapy BP classification Normal SBP* mmHg DBP* mmHg Lifestyle modification <120 and <80 Encourage Without compelling indication Prehypertension 120–139 or 80–89 Yes No antihypertensive drug indicated. Stage 1 Hypertension 140–159 or 90–99 Yes Thiazide-type diuretics for most. May consider ACEI, ARB, BB, CCB, or combination. Stage 2 Hypertension >160 or >100 Yes Two-drug combination for most† (usually thiazide-type diuretic and ACEI or ARB or BB or CCB). *Treatment determined by highest BP category. †Initial combined therapy should be used cautiously in those at risk for orthostatic hypotension. ‡Treat patients with chronic kidney disease or diabetes to BP goal of <130/80 mmHg. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. With compelling indications Drug(s) for compelling indications. ‡ Drug(s) for the compelling indications.‡ Other antihypertensive drugs (diuretics, ACEI, ARB, BB, CCB) as needed. Lifestyle Modification to Manage HBP (Box 10.4) Modification Weight reduction Approximate SBP reduction (range) 5–20 mmHg/10 kg weight loss Adopt DASH eating plan 8–14 mmHg Dietary sodium reduction 2–8 mmHg Physical activity 4–9 mmHg Moderation of alcohol consumption 2–4 mmHg Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Lifestyle Treatment of Hypertension (Box 10.4) Lose weight if overweight Loss of excess weight is the most effective of all lifestyle strategies. See Figure 10.29. Reduce salt intake to less than 6 g/d (1¼ teaspoons) Most people consume a diet that contains well over 1 tsp/day, with about 75% of this from processed foods, not the salt shaker. This is far in excess of body needs, and tends to elevate BP especially as the salt habit is continued into old age. Lowering salt by 0.5 tsp/day reduces sBP by 5 mm Hg. JNC7 recommends less than 2,400 mg/day for prevention of HBP. Learn to read food labels and avoid foods high in sodium, choose more fresh fruits and vegetables, reduce use of salt during cooking while using more herbs and spices, avoid using the salt shaker on prepared foods, and limit the use of foods with visible salt. See Box 10.5 for DASH diet. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Lifestyle and Treatment of Hypertension (cont) Maintain adequate dietary potassium intake Potassium, which is common in fresh fruits and vegetables, helps reduce blood pressure. At least 5-9 servings of fruits and vegetables are recommended each day. See Box 10.5. Limit alcohol intake (see Figures 10.30, 10.31). Heavy alcohol consumption (three drinks or more a day) causes an increase in blood pressure. Males should keep alcohol intake under two drinks a day, and females should aim for less than one drink. (1 alcoholic drink has 0.5 oz pure alcohol = 1 can beer, 1 glass wine, 1.5 oz 80 proof distilled spirits. Each raises BAL 0.02. Liver clears 1 oz alcohol every 3 hours). See Box 10.8. Exercise regularly Regular aerobic exercise is a powerful tool in both preventing and treating high blood pressure. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Exercise and Hypertension During aerobic activity, BP rises strongly, and then falls below normal levels as the blood vessels relax, an effect that can last for at least 30 to 120 minutes (Fig 10.32). Over time, as the exercise is repeated, a long-lasting reduction in resting blood pressure is experienced (Fig 10.34 and 10.35). Those with mild hypertension can expect sBP and dBP to fall 5-7 mm Hg in response to regular aerobic exercise. This benefit is independent of changes in body weight or diet. Weight training does not appear to be as effective in lowering blood pressure as aerobic exercise, although it is an excellent way to increase muscular strength, and is recommended for overall physical fitness. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. High Blood Cholesterol High blood cholesterol is a major risk factor for heart disease. Cholesterol is a waxy substance that circulates in the bloodstream. The body makes it own cholesterol, and also absorbs cholesterol from certain kinds of foods, specifically all animal products (i.e., meats, dairy products, and eggs). Cholesterol is essential for the formation of bile acids (used in fat digestion) and some hormones, and is a component of cell membranes, and brain and nerve tissues. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Cholesterol Levels Every American should know their cholesterol level, and have it checked at least once every five years (or every year if heart disease risk is high). Blood cholesterol levels fall into one of three categories: desirable, borderline high risk, or high risk. (Table 10.9). Desirable: <200 mg/dl Borderline high risk: 200-239 High risk: ≥ 240 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Cholesterol Levels Heart disease is very rare when blood cholesterol is less than 160 mg/dl, and some experts regard this as an optimal level. (Figure 10.37). Children and adolescents should keep their blood cholesterol under 170 mg/dl. Despite an impressive drop from the 1960s, about 17% of Americans still has a high-risk blood cholesterol levels (240 mg/dl and higher). (Figures 10.38, 10.39, 10.40). The average American has a blood cholesterol level of 203 mg/dl, and if present trends continue, the Healthy People 2010 goal of 199 mg/dl will likely be achieved. (Figure 10.39). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Fig. 10.39 (gender and age adapted) 230 Women 222 224 221 220 216 217 215 215 212 210 207 205 211 203 202 200 Men 198 195 188 190 185 180 1971-74 1988-94 1960-62 1976-80 1999-2002 Years 35-44 20-34 55-64 45-54 Age Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 75+ 65-74 "Good" and "Bad" Cholesterol Cholesterol is transported through the blood by carriers called lipoproteins. Two specific types of cholesterol carriers are called low density lipoproteins (LDL) and high density lipoproteins (HDL). (Figures 10.41, 10.42). When cholesterol is carried in the LDL (called LDLcholesterol), this is called "bad" cholesterol because it contributes to the buildup of atherosclerosis, increasing heart disease risk. Try to keep LDL-cholesterol as low as possible. For all age groups, a blood LDL-cholesterol under 100 mg/dl is optimal because heart disease is rare below this level. Children and adolescents should keep their blood LDL-cholesterol under 100 mg/dl. See Box 10.6 for the NCEP treatment plan. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Figure 10.42 Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. ATP III Lipid and Lipoprotein Classification (Table 10.9) LDL Cholesterol (mg/dL)* <100 100–129 130–159 160–189 190 Optimal Near optimal/above optimal Borderline high High Very high *LDL-C = TC – [HDL-C + (0.20 x triglycerides)] Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. HDL-Cholesterol In contrast, HDL-C is called the "good" cholesterol. The HDL carrier acts as a type of shuttle as it takes up cholesterol from the blood and body cells and transfers it to the liver, where it is used to form bile acids. Bile acids pass from the liver to the intestine to aid in fat digestion. Eventually, some of the bile acids pass out of the body in the stool, providing the body with a major route for excretion of cholesterol. HDLs have for this reason been called the "garbage trucks" of the body, collecting cholesterol and transporting it to the liver. Thus if levels of HDL-C are high (i.e., 60 mg/dl or above), the risk of heart disease is decreased. An HDL- cholesterol level of less than 40 mg/dl is considered low or undesirable (ATP III). The total cholesterol:HDL-C ratio is highly predictive of CHD (see Figure 10:43). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Triglycerides High triglycerides predict increased risk of CHD when combined with other risk factors. See Figure 10.44 for mean American levels. Best treated with weight loss, physical exercise, alcohol reduction, and in some people, a decrease in simple carbohydrates (sugar). Table 10.9 shows ATP III norms: <150 mg/dl (normal) 150-199 mg/dl (borderline high) 200-499 mg/dl (high) 500 mg/dl (very high) Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. ATP III Diet Guidelines &Therapeutic Lifestyle Changes Evaluate LDL-C response every 6 weeks – Box 10.7 Saturated fat: <7% of total calories Polyunsaturated fat: Up to 10% of total calories Monounsaturated fat: Up to 20% of total calories Total fat: 25–35% of total calories Carbohydrate: 50–60% of total calories Fiber: 20–30 grams per day Protein: Approximately 15% of total calories Cholesterol: <200 mg/day Total calories (energy): Balance energy intake and expenditure to maintain desirable body weight/prevent weight gain Weight reduction and increased physical activity Consider plant stanols/sterols, and increased water soluble fibers Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. When Drugs Are Needed Table 10.10 Sometimes diet, weight loss, and exercise alone are not enough to control high LDL-cholesterol and low HDL-cholesterol levels. Some individuals are genetically predisposed to high blood cholesterol. If 3 months of lifestyle therapy are unsuccessful in improving blood lipoproteins, medical doctors may prescribe one of several different types of drugs. The most prominent cholesterol drugs are in the statin family, an arra of powerful treatments that includes Mevacor or lovastatin, Pravacho or pravastatin, Zocor or simvastatin, and Lipitor or atorvastatin. These drugs work by interfering with the cholesterol-producing mechanisms of the liver and by increasing the capacity of the liver to remove cholesterol from the blood. Statins can lower LDLcholesterol by as much as 60% and dramatically lower the risk of dying from heart disease. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Table 10.11 Metabolic Syndrome RISK FACTOR Abdominal obesity DEFINING LEVEL Waist circumference Men >40 inches Women >35 inches Triglycerides ≥ 150 mg/dl HDL cholesterol Men < 40 mg/dl Women < 50 mg/dl Blood pressure ≥ 130/ ≥ 85 mm Hg Fasting glucose ≥ 110 mg/dl Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Lifestyle and HDL-C How can one ensure a good blood lipoprotein profile—low total cholesterol and LDLcholesterol, and high HDL- cholesterol? Several lifestyle factors have a strong influence. In order of importance, the factors that increase HDL-cholesterol are: Vigorous aerobic exercise, at least 80-90 minutes per week. Maintaining a lean body weight and avoiding weight gain. Smoking cessation. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Lifestyle and LDL-C The most important factors for lowering LDLcholesterol and total cholesterol are: Reduction of dietary saturated fat intake to less than 10% of calories (found mainly in meats, dairy products, and some tropical oils like palm and coconut oil), with a greater emphasis on most plant oils and fish which are high in unsaturated fats. Reduction in body weight (if high). Reduction in dietary cholesterol intake to less than 300 mg/day (found in foods of animal origin). Increase in carbohydrates to more than 55% of calories and dietary fiber to more than 20 grams/day (especially fruits and vegetables, beans and oat products). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Lifestyle Specifics: Weight Loss Weight loss, in and of itself, has a powerful effect on blood fats and lipoproteins. With weight loss, total cholesterol, LDL-cholesterol, and triglycerides decrease strongly, while HDL-cholesterol increases (but only when weight loss has been maintained and stabilized). The total cholesterol drops about 1 mg/dl for every pound lost (decreases are greatest for those with the highest blood cholesterol levels). In other words, if a woman changes her weight from 180 to 160 pounds, her blood cholesterol could be expected, on average, to decrease 20 mg/dl (e.g., from 205 to 185 mg/dl). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Lifestyle: Dietary Habits Improvements in dietary habits also have a favorable effect on blood lipids and lipoproteins. Going from the typical American diet to the one recommended by the American Heart Association can decrease the total cholesterol by 5% to 15% (depending on the initial level). Most of the improvements in blood lipids happen quickly, within the first two weeks, upon adoption of a heart-healthy diet and weight loss regimen. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. American Heart Association Guidelines for Reducing the Risk of Cardiovascular Disease by Dietary and Other Lifestyle Practices (Box 10.8). 1. A Healthy Eating Pattern Including Foods From All Major Food Groups A. Consume a variety of fruits and vegetables; choose 5 or more servings per day. B. Consume a variety of grain products, including whole grains; choose 6 or more servings per day. 2. A Healthy Body Weight A. Match intake of total energy (calories) to overall energy needs. B. Achieve a level of physical activity that matches (for weight maintenance) or exceeds (for weight loss) energy intake. Walk or do other activities for at least 30 minutes on most days. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 3. A Desirable Blood Cholesterol and Lipoprotein Profile A. Limit intake of foods with high content of cholesterolraising fatty acids. • Keep saturated fat intake at less than 10% (<7% for those with high LDL-C). Include fat-free and low-fat milk products, fish, legumes (beans), skinless poultry and lean meats. Choose fats with 2 gm or less saturated fat/serving, such as liquid and tub margarines, canola oil, and olive oil. Limit intake of full-fat milk products, fatty meats, and tropical oils. • Limit intake of trans-fatty acids, the major contributor of which is hydrogenated fat. B. Limit the intake of foods high in cholesterol. • Limit dietary cholesterol intake to less than 300 mg/day on average (<200 mg/day for individuals with elevated LDL cholesterol, diabetes, and/or cardiovascular disease). C. Substitute grains and unsaturated fatty acids from fish, vegetables, legumes, and nuts. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. 4. A Desirable Blood Pressure A. Limit salt (sodium chloride) intake to 6 grams/day (100 mmol or 2,400 mg of sodium). B. Maintain a healthy body weight. C. Limit alcohol intake among those who drink (no more than 2 drinks per day for men, and 1 drink per day for women). D. Maintain a dietary pattern that emphasizes fruits, vegetables, and low-fat dairy products and is reduced in fat. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Issues That Merit Further Research Antioxidants: High intake of antioxidants from plant foods is recommended; insufficient evidence to support supplements. B Vitamins and Homocysteine Lowering: The normal metabolism of homocysteine requires an adequate supply of folate, B6, B12, and riboflavin. High plasma homocysteine has been related to increased CHD risk in most but not all studies. Soy Protein and Isoflavones: The consumption of soy protein in place of animal protein tends to lower blood levels of cholesterol, LDL-C, and triglycerides without affecting HDL-C. Omega-3 Fatty Acid Supplements: Consumption of one fatty fish meal per day (or alternatively, a fish oil supplement) could result in an omega-3 fatty acid intake of about 900 mg/day, an amount shown to beneficially affect coronary heart disease mortality rates in patients with coronary disease. Stanol/Sterol Ester-Containing Foods: Stanol/sterol ester (plant sterols)containing foods have been shown to decrease blood cholesterol levels. Plant sterols (currently isolated from soybean and tall oils, esterified, and then incorporated into food products) decrease total and LDL cholesterol by decreasing intestinal absorption of dietary cholesterol. Fat Substitutes: Fat substitutes mimic one or more of the roles of fat in a food, and tend to reduce fat and energy intake. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Exercise and Dyslipidemia Early studies showed that HDL-C was higher in runners compared to controls (Figure 10.46). Recent cross-sectional studies show a doseresponse between miles run per week and HDL-C (Figure 10.47). People who exercise regularly also have lower total blood cholesterol and LDL-C, but this appears to be more closely related to body mass and diet factors. When changes in body mass and dietary habits are controlled, exercise training alone can be expected to increase HDL-C and to decrease triglyceride levels, with little or no effect on LDL-C. See Figures 10.48, 10.49, and 10.51. Figure 10.50 summarizes potential mechanisms. Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved. Exercise and Heart Disease Physical inactivity doubles the risk for CHD, while regular activity cuts the risk in half (see Figures 10.52, 10.53, 10.54). A growing number of studies show that regular physical activity also lowers risk of stroke (Figures 10.57, 10.58). This is similar to the effect of high blood pressure, high blood cholesterol, and cigarette smoking on CHD risk. Physical activity must be a current and regular lifestyle habit in order for CHD risk to be lowered, however. In other words, exercise habits of years gone by are insufficient for today. About 30 minutes of moderate-intensity physical activity a day is sufficient, with CHD risk lowered even further when greater amounts of more vigorous exercise are engaged in (Figure 10.56). Can physical activity be used to treat CHD? Yes, especially when combined with other lifestyle changes such as smoking cessation, weight control, and dietary improvement (see Figure 10.59). Nieman DC. Exercise Testing and Prescription: A Health-Related Approach. 6/e. Copyright ©2007 McGraw-Hill Higher Education. All rights reserved.