Other Lipids. Elevated levels of other fatty molecules (lipids) are also now thought to be important indicators of heart disease risk. Studies are finding an elevated risk for angina and first heart attacks in people with elevated levels of lipoprotein(a), or lp(a). This lipoprotein falls somewhere in density between HDL and LDL and may have some properties that increase the risk for blood clots. Some experts suggest, however, that high levels of lp(a) may merely be markers of late-stage atherosclerosis, not a cause.
[For more information, see In-Depth Reports #23: Cholesterol and #43: Heart-healthy diet.]
High Blood Pressure
High blood pressure, or hypertension, has long been a proven cause of coronary artery disease. Blood pressure is categorized as normal, prehypertensive, and hypertensive (which is further divided as Stage 1 or 2 according to severity). High blood pressure is generally considered to be a blood pressure reading greater than or equal to 140 mm Hg (systolic) or greater than or equal to 90 mm Hg (diastolic). Blood pressure readings in the prehypertension category (120-139 systolic or 80-89 diastolic) indicate an increased risk for developing hypertension. [See Table Blood Pressure Ranges.]
A normal blood pressure reading is 120/80 mm Hg or lower. Most people with high blood pressure should aim for a goal of below 140/90 mm Hg. Patients with certain health problems should aim lower (blood pressure in patients with kidney disease, heart failure, or diabetes should be equal to or lower than 130/80 mm Hg.)
 | Click the icon to see an image about hypertension. |
Blood Pressure Ranges |
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Blood Pressure Category |
Ranges for Most Adults (systolic/diastolic) |
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Normal Blood Pressure (systolic/diastolic) |
Systolic below 120 mm Hg Diastolic below 80 mm Hg |
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Prehypertension (Formerly Classified as Normal to High-Normal Blood Pressure) |
Systolic 120 to 139 mm Hg Diastolic 80 to 89 mm Hg (NOTE: 139/89 or below should be the minimum goal for everyone. People with diabetes or chronic kidney disease should strive for 130/80 or less.) |
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Mild Hypertension (Stage 1) |
Systolic 140 to 159 mm Hg Diastolic 90 to 99 mm Hg |
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Moderate to Severe Hypertension (Stage 2) |
Systolic over 160 mm Hg and/or Diastolic over 100 mm Hg |
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Note: If one of the measurements is in a higher category than the other, the higher measurement is usually used to determine the stage. For example, if systolic pressure is 165 (Stage 2) and diastolic is 92 (Stage 1), the patient would still be diagnosed with Stage 2 hypertension. A high systolic pressure should be a major focus of concern in most adults. |
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Obesity and Metabolic Syndrome
American obesity is at epidemic levels in all age groups. The effect of obesity on cholesterol levels is complex. Although obesity does not appear to be strongly associated with overall cholesterol levels, among obese individuals triglyceride levels are usually high while HDL (beneficial cholesterol) levels tend to be low, both risk factors for heart disease. Obesity has other effects (hypertension, increase in inflammation) that pose major risks to the heart.
 | Click the icon to see an image of childhood obesity. |
Obesity is particularly hazardous when it is one of the components of the metabolic syndrome. This syndrome is diagnosed when three of the following are present: abdominal obesity, low HDL cholesterol, high triglyceride levels, high blood pressure, and insulin resistance. Metabolic syndrome is a pre-diabetic condition that is significantly associated with heart disease and higher mortality rates from all causes. A 2002 study estimated that 24% of the population now has this condition. Obesity is highly linked with type 2 diabetes, and diabetes itself poses a significant risk for high cholesterol levels and heart disease.
Some obese patients with coronary artery disease may consider having bariatric surgery (stomach bypass) to lose excess weight. The weight lost after surgery can help improve blood pressure, cholesterol, blood sugar and other factors associated with CAD. A 2005 study reported that bariatric surgery is safe for patients with CAD who cannot lose weight with diet and exercise, which should always be tried first.
[For more information, see In-Depth Report #53: Weight control and diet.]
Sedentary Lifestyle and Exercise
People who are sedentary are almost twice as likely to suffer heart attacks as are people who exercise regularly. Exercise has a number of effects that benefit the heart and circulation, including improving cholesterol and lipid levels, reducing inflammation in the arteries, assisting weight loss programs, and helping to keep blood vessels flexible and open. Studies continue to show that physical activity and avoiding high-fat foods are the two most successful means of reaching and maintaining heart healthy levels of fitness and weight.
Experts have been attempting to define how much exercise is needed to produce heart benefits. In 2002, a well-conducted study on overweight adults confirmed previous research that reported beneficial changes in cholesterol and lipid levels even when people performed low amounts of moderate or high intensity exercise (walking or jogging 12 miles a week). However, more intense exercise is required to significantly change cholesterol levels, notably by increasing HDL (the so-called good cholesterol). Overweight people who have trouble losing pounds can still achieve considerable heart benefits by exercising. Resistance (weight) training has also been associated with heart protection. Exercises that train and strengthen the chest muscles may prove to be very important for patients with angina.
 | Click the icon to see an image about exercise. |
 | Click the icon to see an image about hypertension and lifestyle changes. |
Some studies suggest that for the greatest heart protection, it is not the duration of a single exercise session that counts but the total daily amount of energy expended. Therefore, the best way to exercise may be in multiple short bouts of intense exercise, which can be particularly helpful for older people.
Sudden strenuous exercise (such as snow shoveling and mowing lawns) puts many people at risk for angina and heart attack. Activities that involve raising the arms above the head may also be risky. Patients with angina should never exercise shortly after eating. People with risk factors for heart disease should seek medical clearance and a detailed exercise prescription. And all people, including healthy individuals, should listen carefully to their bodies for signs of distress as they exercise. [For more information, see In-Depth Report #29: Exercise.]
Diabetes and Insulin Resistance
Heart disease and stroke are the leading causes of death in people with diabetes. People with diabetes are at risk for the following heart-risk conditions, and the more of these conditions they have, the worse the outlook.
- High blood pressure (hypertension). Up to 75% of cardiovascular problems in people with diabetes may be due to hypertension.
- Very unhealthy cholesterol and lipid balances (high triglyceride levels and lower HDL).
- Blood clotting problems.
- Impaired nerve function (neuropathy), which can also damage the heart. Some experts estimate that the mortality rates from neuropathy-related heart conditions range from 15 - 53%.
People with both diabetes and heart disease may have a higher risk for silent ischemia, a condition in which people have blocked arteries but do not experience the angina, the chest pain that signals heart disease. [For more information, see In-Depth Reports #9: Diabetes - type 1 or #60: Diabetes - type 2.]
Peripheral Artery Disease
Peripheral artery disease (PAD) occurs when atherosclerosis affects the extremities, particularly the feet and legs. The major risk factors for heart disease and stroke are also the most important risk factors for PAD. (The combination of such conditions with PAD also produces more severe forms of heart or circulatory disease.) Although signs of heart disease are detected in only 20 - 40% of patients with PAD after an initial diagnosis, studies suggest that when intense heart-diagnostics tests are performed, such as angiography or thallium stress tests, co-existing heart disease is detected in up to 90% of all PAD patients. [For more information, see In-Depth Report #102: Peripheral artery disease.]
Smoking
Smokers in their 30s and 40s have a heart-attack rate that is five times higher than their nonsmoking peers. Cigarette smoking may be directly responsible for at least 20% of all deaths from heart disease, or about 120,000 deaths annually. Smoking cigars may increase the risk of early death from heart disease, although evidence is much stronger for cigarette smoking. Although heavy cigarette smokers are at greatest risk, a 2002 study suggested that people who smoke as few as three cigarettes a day are at higher risk for blood vessel abnormalities that endanger the heart. Regular exposure to passive smoke also increases the risk of heart disease in nonsmokers. [For more information, see In-Depth Report #41: Smoking.]
Eating Habits
Eating habits can be protective or dangerous to the heart. Avoiding saturated fats and trans-fatty acids is particularly important for controlling cholesterol.
Dietary Factors and Heart DiseaseDiet plays an important role in the health of the heart. Although there are many major dietary approaches for protecting health, experts generally agree on the following recommendations for heart protection:
[For more information, see In-Depth Report #43: Heart-healthy diet.] Mediterranean Diet. The Mediterranean diet is rich in heart-healthy fiber and nutrients, including omega-3 fatty acids and antioxidants. The diet consists of fruits, vegetables, and unsaturated "good" fats, particularly olive oil. There are several variations to the Mediterranean diet but general recommendations include:
Therapeutic Lifestyle Changes (TLC) from the National Cholesterol Education Program. Guidelines from the National Cholesterol Education Program include these recommendations for preventing and managing high cholesterol levels in adults:
Low Fat Diets. Dietary guidelines recommend keeping total fat intake to 20 – 30% of total daily calories, with saturated fat less than 10% of calories. Low-fat diets generally restrict fat intake to 20% or less of total daily calories. The Ornish program, which is recommended for some heart disease patients, limits fats even more drastically. It aims at reducing saturated fats as much as possible, restricting total fat to 10%, and increasing carbohydrates to 75% of calories. In 2006, the largest study to date on low-fat diets found that they did not help prevent heart disease or cancer. Women in the study reduced their fat consumption to 24 – 29% of total daily calories. Some critics say that the study did not do enough to distinguish between good types of fats (monounsaturated omega-3 polyunsaturated) and bad fats (saturated and trans fats). Low Carbohydrate Diets. Diets that restrict carbohydrate intake include the Atkins, South Beach, The Zone, and others. A 2006 review of low-carbohydrate diets found that they did help weight loss in the short term. However, while these diets appeared to lower triglyceride and raise HDL (“good”) cholesterol levels, they also raised overall and LDL (“bad”) cholesterol levels. There is not yet enough evidence to indicate whether the good heart effects of these diets outweigh the bad effects. At this time, experts do not recommend low-carbohydrate diets for heart disease prevention. The DASH Diet. The DASH diet (Dietary Approaches to Stop Hypertension) helps lower blood pressure and may have other heart benefits as well. Restricting sodium improves results. This diet is not only rich in important nutrients and fiber but also includes foods that contain far more electrolytes, potassium, calcium, and magnesium, than are found in the average American diet. The dietary recommendations are:
Calorie Restriction. Calorie restriction has been the cornerstone of weight-loss programs. Restricting calories appears to have beneficial effects on cholesterol levels, including reducing LDL and triglycerides and increasing HDL levels. A 2006 study reported that a low-calorie, but nutritionally balanced diet can help prevent an aging-associated change in heart function. Patients in the small study took in 1,400 - 2,000 calories a day for an average of 6 years. The standard dietary recommendations for losing weight are:
[For more information, see In-Depth Report #53: Weight control and diet.] |
Stress and Psychologic Factors
Stress. The effects of mental stress on heart disease are controversial. Stress can affect the heart when it activates the sympathetic nervous system (the automatic part of the nervous system that affects many organs, including the heart). Some studies suggest an association between acute stress and a higher risk for serious cardiac events, such as heart rhythm abnormalities and heart attacks, in people with heart disease. However, not all studies report strong evidence that stress has any effect on the heart, particularly in people without any history of heart disease. [See In-Depth Report #31: Stress.]
Depression. Depression increases the severity of heart attack and may even worsen a patient's response to medication for heart disease. Although people with heart disease may become depressed, this does not explain entirely the link between the two problems. Data now suggest that depression itself may be a risk factor for heart disease as well as its increased severity. A number of studies indicate that depression has biologic effects on the heart, including blood clotting and heart rate. One study, for example, reported an association between depression and a greater risk for death from heart problems even in people without a history of heart disease. Another study reported a higher risk for heart failure in women -- although not in men -- with depression. The more severe the depression, the more dangerous to the health. Even mild depression, which includes feelings of hopelessness experienced over many years, may harm the heart. [See In-Depth Report #8: Depression.]
Alcohol
Benefits of Moderate Drinking. Several studies have found heart protection from moderate intake of alcohol (one or two glasses a day). Moderate alcohol consumption can help boost HDL levels. Alcohol may also prevent blood clots and inflammation. Although red wine is most often cited for healthful properties, any type of alcoholic beverage appears to have similar benefit.
Adverse Effects of Heavy Drinking. By contrast, heavy drinking harms the heart. In fact, heart disease is the leading cause of death in alcoholics. Evidence suggests that people who consume more than three drinks a day have abnormal blood clotting factors. Heavy alcohol consumption can raise blood pressure, and binge drinking may increase the risk for hemorrhagic stroke (caused by bleeding in the brain). Large doses of alcohol can trigger irregular heartbeats, which can be dangerous in people with existing heart disease.
Pregnant women and people who can't drink moderately should not drink at all.
Emerging or Possible Risk Factors for Heart Disease
Homocysteine and Vitamin B Deficiencies. Deficiencies in the B vitamins folate (known also as folic acid), B6, and B12 have been associated with a higher risk for heart disease in some studies. Such deficiencies produce higher blood levels of homocysteine, an amino acid that has been associated with a higher risk for heart disease, stroke, and heart failure. Researchers have been studying whether vitamin B supplements can reduce homocysteine levels and, consequently, heart disease risks. Several major 2006 studies indicated that while B vitamin supplements do help lower homocysteine levels, they have no effect on heart disease outcomes. The studies, published in the New England Journal of Medicine, examined patients who had either recently had a heart attack or suffered from diabetes or heart disease. Results showed a similar number of heart attacks and strokes among patients who took B vitamins and those who received placebo. Some experts think that homocysteine may be a marker for heart disease rather than a cause of it.
 | Click the icon to see the benefits of vitamin B. |
 | Click the icon to see the food sources of vitamin B. |
C-Reactive Protein. C-reactive protein is a product of the inflammatory process. Evidence increasingly suggests that high levels strongly predict future heart disease. Some studies indicate that measuring this protein may be as useful for determining future risk for heart disease as measuring LDL cholesterol levels. It is not known if the protein plays any causal role or whether it is simply a marker for other factors in the disease process.
C. pneumoniae and Other Infectious Organisms. Some microorganisms and viruses have been under suspicion for triggering the inflammation and damage in the arteries that contribute to heart disease. The strongest evidence to date supports a possible role from Chlamydia (C.) pneumoniae (a non-bacterial organism that causes mild pneumonia in young adults). C. pneumoniae has been detected in plaques in the arteries of patients with heart disease. In some studies, evidence of previous infection has been associated with a higher risk for heart events.
Other studies also suggest that cytomegalovirus (CMV), a common virus, may have similar effects. Many people, however, have been infected with these organisms, and no clear association has been found with any of these infections.(H. pylori, the bacteria that causes peptic ulcers, has also been studied for heart effects, but evidence is very weak on any link.)
Erectile Dysfunction. Recent research suggests that erectile dysfunction may be a warning sign of coronary artery disease, even in men who are not considered at risk for the condition. Some studies indicate that men with erectile dysfunction have higher levels of C-reactive protein and more symptoms of atherosclerosis than men without erectile problems.
Periodontal Disease. A number of studies now strongly supports an association between periodontal disease and cardiovascular disorders. According to a 2003 major analysis, periodontal (gum) disease is associated with a 20% higher risk for ischemic stroke and heart disease. (The added risk may be even higher in adults under 65.) Recent evidence is pointing to the inflammatory response as the common element.
 | Click the icon to see an image of gum disease. |
Anemia. Anemia has adverse effects on the heart and increases the severity of cardiac conditions, including heart failure and heart attacks. A 2002 study suggested that anemia may even be a risk factor for heart disease itself. Blood transfusions after a heart attack improve survival rates in elderly patients who are anemic.
Iron Overload. An inherited disease called hemochromatosis, in which the intestinal tract absorbs too much iron from food, has been associated with atherosclerosis and heart attack. About 10% of Caucasians carry the gene for this condition. There is no strong evidence that excess iron levels in people without hemochromatosis can contribute to heart disease.
Sleep Apnea. Obstructive sleep apnea is a condition in which tissues in the upper throat collapse at intervals during sleep, thereby blocking the passage of air. It has been strongly associated with high blood pressure and obesity, but is also associated with heart disease and heart attacks, regardless of these risk factors. Some evidence suggests that obstructive apneas cause an increase in stiffness and inflammation in the arteries.
Conditions Associated with Heart Disease
Some inborn or natural conditions are not risk factors themselves but have been associated with a higher incidence of heart disease or its consequences:
Factors Before Birth and In Infancy. Low weight at birth and in the womb has been associated with later heart disease in a few studies. Some suggest, however, that this may just reflect poor nutrition in the mother, which appears to affect life-long risk.
Seasonal Differences. More deaths from heart disease occur in December and January, and fewest in the summertime. Although lower temperatures and snow shoveling may play a role in some cases, more winter deaths have been reported even in warm regions. Holiday stress or fewer daylight hours have been suggested as other reasons for these higher winter rates.
Physical Characteristics. Male pattern baldness, hair in the ear canals, and creased earlobes are associated with a higher risk for heart disease in Caucasian males.
 | Click the icon to see an image of an ear lobe crease. |
Air Pollution. A 2000 study suggested that air pollution is linked to a higher risk of death from heart disease as well as lung disease.
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