Aspirin works by preventing platelets in the blood from clumping together--reducing the chance that a blood clot will form in an artery that already is narrowed because of the buildup of plaque. Studies show that people who have suffered a heart attack can reduce the chance of a second attack by taking an aspirin a day.

The American Heart Association recommends that people who have had a heart attack, unstable angina, ischemic stroke or transient ischemic attacks (known as TIAs or "little strokes") consider taking regular aspirin after consultation with their doctor; others recommend it as a preventative measure against first attacks in people with multiple coronary risk factors. Most doctors in the United States prescribe 325 mg of aspirin a day, the amount in one adult aspirin pill. European physicians, however, tend to prescribe less aspirin, typically about 75 mg a day, or the amount in one baby aspirin, which is sufficient to provide protection. The amount of aspirin you take to prevent a second attack will depend on how old you are and whether you suffer any side effects from higher doses of the drug. However, people with liver or kidney disease, stomach ulcers, other gastrointestinal diseases, bleeding problems or an allergy to aspirin are at greatest risk from regular aspirin use. But even if you don't have any of these conditions, regular aspirin use may cause gastrointestinal irritation or bleeding.

2. I exercise, eat right and live a heart-healthy lifestyle that includes not smoking and regular stress management. But heart disease runs in my family. Should I worry?

Your risk of developing coronary artery disease is higher if one or both of your parents or a sibling developed the disease before age 55. The greatest inherited risk of heart disease is in people with a genetic predisposition to have dangerously high cholesterol levels, a condition known as familial hypercholesterolemia, which is marked by blood cholesterol above 300 mg/dl. You can help offset the inherited risk by continuing to practice the healthy lifestyle you describe, and by having your physician review your cholesterol profile and other risk factors.

3. How does menopause influence cardiovascular disease?

Estrogen boosts levels of protective HDL cholesterol, which helps to remove cholesterol from atherosclerotic plaques. So as estrogen levels decline at menopause, a woman's risk of heart disease increases. About 3,000 women between the ages of 29 and 44 have a heart attack each year; that figure climbs to 136,000 among women aged 45 to 64, and skyrockets to 374,000 in women over age 65. Estrogen replacement therapy seems to reduce osteoporosis, the bone-thinning disease, and helps control symptoms of menopause like hot flashes. But estrogen may increase your risk of uterine cancer and possibly breast cancer, and recent research has shown that it slightly increases a woman's risk of cardiovascular problems. Therefore, it is no longer recommended for prevention of heart disease. It may still be a reasonable medication, however, for women who have intolerable symptoms of menopause.

4. How does stress influence cardiovascular disease?

When an event is perceived as a threat, the "stress" hormones of adrenaline and cortisol (made by the adrenal glands) flood the body, increasing the heart's need for oxygen as it prepares for vigorous action. Heart rate and blood pressure increase and blood vessels in your skin constrict. The tendency for blood to clot increases and the body's cells pour stored fat into the bloodstream. Add it all up and it puts additional strain on the heart and artery linings — and an increased risk of heart disease.

The problem is not stress itself, but the reaction to it. Practicing some form of stress management or relaxation — such as meditation — can help prevent the "fight-or-flight" response that triggers the release of stress hormones.

5. Does caffeine play a role in heart disease?

Caffeine is a stimulant, so it revs up the nervous system and causes a slight acceleration in heart rate. However, there is no evidence that moderate amounts of caffeine — two or so cups of coffee each day — are dangerous.

6. Why are African-Americans more prone to heart disease?

Compared with whites, blacks develop high blood pressure at an earlier age. And no matter their age, the disease is more severe in blacks than in whites. Because high blood pressure increases the risk of other cardiovascular diseases, blacks are 1.8 times more likely to have a nonfatal stroke, 1.3 times more likely to have a fatal stroke, and 1.5 times more likely to die from heart disease than are whites.

Despite many theories trying to explain these inequalities in the risk of developing and dying from heart disease, doctors have had difficulty determining the exact reasons. One theory is that blacks are less likely to have access to health care. And high blood pressure is thought to be more common in blacks because of racial differences in the way sodium is excreted by the body. Some doctors believe that blacks retain more sodium than whites, a factor that can work to increase blood pressure.

7. Is it possible to eat a "no-cholesterol" diet and still have high blood cholesterol?

Definitely! First of all, cholesterol is produced in your body (the liver makes about 2,000 milligrams a day), so some of that winds up in your blood anyway. Dietary cholesterol is only present in food that comes from animals--like meats, dairy products, eggs--but even though strict vegetarians consume little or no cholesterol-containing foods, they can have high blood cholesterol if they have inherited a gene for high cholesterol and because foods high in saturated fats can raise cholesterol even more than high-cholesterol foods. The key is to limit your intake of saturated fats to no more than 10 percent of total calories.

8. Does body shape play any role in cardiovascular disease?

Being obese is a definite risk factor, but the location of your extra fat also has some bearing: People who are "apple-shaped," where most fat is in the mid-section, have a higher risk of heart disease than those who are "pear-shaped," where fat is mostly concentrated in the hips and buttocks.

9. How often should I see my doctor for a heart disease checkup?

Most experts agree that if you are healthy, you should get a regular checkup at least twice during your 20s (every 5 years), three times during your 30s (every 3 to 4 years), four times during your 40s (every 2 to 3 years), five times during your 50s (every 2 years), and every year once you reach age 60.

10. How common is heart disease?

While science has made tremendous strides in fighting cardiovascular disease, it's still the number one killer in the United States. Cardiovascular disease is responsible for nearly half of all deaths every year; one American dies from it every 33 seconds.