• Quit smoking. Cigarettes increase blood pressure and plaque buildup in arteries and decrease levels of HDL, the good cholesterol.
• Eat well. Cook with heart-healthy monounsaturated oils, such as olive and canola. If you eat red meat, do so infrequently and go lean. If you drink milk or eat dairy, opt for skim or low-fat. Use butter sparingly. Eat plenty of vegetables, fruits, whole grains, nuts, and legumes.
• Pay attention to portion sizes. Think of your plate in three sections: one for protein (the size and thickness of a deck of cards), one for carbohydrates (the size of your fist), and one for vegetables, especially leafy greens.
• Stay active. Aim for at least three to five 30-minute stints of heart rate-raising exercise a week. Regular workouts keep blood vessels in good shape and pumping efficiently.

• Develop healthy habits now. Heart attacks are rare in women in their 20s, but heart disease is something you develop gradually. The habits you have in your 20s and 30s will affect your health for the rest of your life.
• Maintain a healthy weight. Being overweight is a risk factor for diabetes, which is in turn a risk factor for heart disease. Watch your diet and exercise regularly.
• Learn about your history. If a man in your family had heart disease before age 55 or a woman had it before age 65 that counts as a strong family history. Be on the lookout for polycystic ovarian syndrome. This hormonal condition can raise the risk for heart disease later in life.

• Blood pressure: Annually.
• Body-mass index (BMI), waist circumference, and/or waist-to-hip ratio measurement: Annually.
• Lipid panel: By age 20; repeat annually or more often if your lipids are in an unhealthy range, or every five years if they're in a healthy range.
• Fasting blood glucose: Only if you're diabetic, pregnant, or at risk for diabetes (this includes anyone with a BMI of 25 or higher; those with a family history of diabetes; and African-Americans, Native Americans, and Hispanics).

• Push yourself at the gym. Regular exercise that includes resistance training helps counter the loss of muscle mass, which occurs at a rate of half a pound per year from the age of 25. Less muscle mass can mean more fat, which is hard on the heart.
• Watch the scale. After age 30, Americans often gain a pound a year.
• Manage stress. The increasing demands of family, work, and social life make you vulnerable to anxiety and depression, both of which threaten your heart. Depression may lead to unhealthy habits, such as smoking and excessive drinking, while stress can precipitate an event like a heart attack.
• Keep the risk of diabetes on your radar. Heart disease affects people with diabetes twice as often as those without it.

Everything as in your 20s.

• Find a medical ally. Your doctor will identify factors that may be raising your heart-disease risk, counsel you on how to lower that risk, and administer tests and medication as needed.
• Consider medications. Lifestyle changes alone may still be enough to cut your risk to normal. But medication to control blood pressure, lower cholesterol, and manage blood sugar may be necessary, too.
• Don't get stuck in the middle. That pudge around your waist spikes blood pressure and cholesterol. Fortunately, a little strength training can help stave it off.

Everything as in your 20s and 30s plus:

• Electrocardiogram: In your early 40s if your risk is high.
• Stress test: In your early 40s if your risk is high.
• Fasting blood glucose: Every three years starting at age 45 if there are no risk factors, or more often if you are overweight or have other risk factors.

• Get moving. Menopause depletes levels of heart-protective estrogen, making blood vessels less flexible (exercise helps counteract this).
• Monitor your risk factors. Blood pressure and triglyceride levels may edge up, especially if you have put on weight or are taking an oral estrogen replacement.
• Know the signs of heart attack. In addition to the typical male symptoms (pain or pressure in the center of the chest radiating to the neck and arms), women may feel severe indigestion, lower-chest and upper-abdominal pain, unexplained shortness of breath, sweating, nausea, upper-back pain, shoulder pain, or severe fatigue. If you experience any of these, head to an ER.

Everything as in your 40s plus:

• High-sensitivity C-reactive protein, homocysteine, and/or lipoprotein: As indicated by your doctor, based on your risk factors.