1. Don't smoke or use tobacco products

"If you smoke, quit," advises Sharonne Hayes, M.D., a cardiologist and director of the Women's Heart Clinic at Mayo Clinic, Rochester, Minn. "That's the most powerful, preventable risk factor for heart disease."

When it comes to heart disease prevention, no amount of smoking is safe. Smokeless tobacco and low-tar and low-nicotine cigarettes also are risky, as is exposure to secondhand smoke.

Tobacco smoke contains more than 4,800 chemicals. Many of these can damage your heart and blood vessels, making them more vulnerable to narrowing of the arteries (atherosclerosis). Atherosclerosis can ultimately lead to a heart attack.

In addition, the nicotine in cigarette smoke makes your heart work harder by constricting blood vessels and increasing your heart rate and blood pressure. Carbon monoxide in cigarette smoke replaces some of the oxygen in your blood. This increases your blood pressure by forcing your heart to work harder to supply enough oxygen. Even so-called "social smoking" — only smoking while at a bar or restaurant with friends — is dangerous and increases the risk of heart disease.

Women who smoke and take birth control pills are at greater risk of having a heart attack or stroke than are those who don't do either. Worse, this risk increases with age, especially over 35.

The good news, though, is that when you quit smoking, your risk of heart disease drops dramatically within just one year. And no matter how long or how much you smoked, you'll start reaping rewards as soon as you quit.

2. Get active

You already know that physical activity is good for you. But you may not realize just how good it is for you.

Regularly participating in moderately vigorous physical activity can reduce your risk of fatal heart disease by nearly a quarter. And when you combine physical activity with other lifestyle measures, such as maintaining a healthy weight, the payoff is even greater.

Regular physical activity helps prevent heart disease by increasing blood flow to your heart and strengthening your heart's contractions so that your heart pumps more blood with less effort. Physical activity also helps you control your weight and can reduce your chances of developing other conditions that may put a strain on your heart, such as high blood pressure, high cholesterol and diabetes. It also reduces stress, which may also be a factor in heart disease.

Federal guidelines recommend that you get at least 30 to 60 minutes of moderately intense physical activity most days of the week. However, even shorter amounts offer heart benefits, so if you can't meet those guidelines, don't give up. And remember that things like gardening, housekeeping, taking the stairs and walking the dog all count toward your total. You don't have to exercise strenuously to achieve benefits, but you can see bigger benefits by increasing the intensity, duration and frequency of your workouts.

3. Eat a heart-healthy diet

Consistently eating a diet rich in fruits, vegetables, whole grains and low-fat dairy products can help protect your heart. Legumes, low-fat sources of protein and certain types of fish also can reduce your risk of heart disease.

Limiting your intake of certain fats also is important. Of the types of fat — saturated, polyunsaturated, monounsaturated and trans fat — saturated fat and trans fat increase the risk of coronary artery disease by raising blood cholesterol levels. Major sources of saturated fat include beef, butter, cheese, milk, and coconut and palm oils. There's growing evidence that trans fat may be worse than saturated fat because unlike saturated fat, it both raises your LDL (bad) cholesterol and lowers your HDL (good) cholesterol. Sources of trans fat include deep-fried fast foods, bakery products, packaged snack foods, margarines and crackers.

Heart-healthy eating isn't all about cutting back, though. Most people, for instance, need to add more fruits and vegetables to their diet — with a goal of five to 10 servings a day.

"There's a huge amount of data to suggest that fruits and vegetables are highly effective in preventing not just cardiovascular disease, but cancer and other diseases as well," Dr. Hayes says.

Omega-3 fatty acids, a type of polyunsaturated fat, may decrease your risk of heart attack, protect against irregular heartbeats and lower blood pressure. Some fish are a good natural source of omega-3s. However, pregnant women and women of childbearing age should avoid shark, swordfish, king mackerel and tilefish because they contain levels of mercury high enough to pose a danger to a developing fetus. But for most others, the health benefits of fish outweigh any risks associated with mercury. Omega-3s are present in smaller amounts in flaxseed oil, walnut oil, soybean oil and canola oil, and they can also be found in supplements.

Following a heart-healthy diet also means drinking alcohol only in moderation — no more than two drinks a day for men, one a day for women. At that moderate level, alcohol can have a protective effect on your heart. Above that, it becomes a health hazard.

4. Maintain a healthy weight

As you put on weight in adulthood, you gain mostly fatty tissue. This excess weight can lead to conditions that increase your chances of heart disease — high blood pressure, high cholesterol and diabetes.

How do you know if your weight is healthy? One way is to calculate your body mass index (BMI), which considers your height and weight in determining whether you have a healthy or unhealthy percentage of body fat.

BMI numbers 25 and higher are associated with higher blood fats, higher blood pressure, and an increased risk of heart disease and stroke.

The BMI is a good but imperfect guide. Muscle weighs more than fat, for instance, and women and men who are very muscular and physically fit can have high BMIs without added health risks. Because of that, waist circumference is also a useful tool to assess abdominal fat. In general, men are considered overweight if their waist measurement is greater than 40 inches. And women, in general, are overweight if their waist measurement is greater than 35 inches.

Even small reductions in weight can be beneficial. Reducing your weight by just 10 percent can decrease your blood pressure, lower your blood cholesterol level and reduce your risk of diabetes.

5. Get regular health screenings

High blood pressure and high cholesterol can damage your cardiovascular system, including your heart. But without testing for them, you probably won't know whether you have these conditions. Regular screening can tell you what your numbers are and whether you need to take action.

• Blood pressure. Regular blood pressure screenings start in childhood. Adults should have their blood pressure checked at least every two years. You may need more frequent checks if your numbers aren't optimal or if you have other risk factors for cardiovascular disease. Optimal blood pressure is less than 120/80 millimeters of mercury.
• Cholesterol levels. Adults should have their cholesterol measured at least once every five years. You may need more frequent testing if your numbers aren't optimal or if you have other risk factors for cardiovascular disease. Some children may need their blood cholesterol tested if they have a strong family history of heart disease.