Many of us are concerned about preventing heart disease. We know that being overweight and having high cholesterol levels are contributors to heart disease. So, diet and exercise are critical in the heart disease fight, because they help to lower cholesterol levels.

However, it's also important to protect our endothelial and platelet function. Endothelial dysfunction is a serious precursor to heart disease, and often appears many years before other serious signs of cardiovascular disease. It is estimated that endothelial dysfunction affects about 50% of people over the age of 40.

The endothelium lines the inner surface of all blood vessels including arteries and veins. The endothelium is responsible for mediation of coagulation, platelet adhesion, immune function, and control of volume and electrolyte content of the intravascular and extra vascular spaces.

Several things can cause endothelial dysfunction. The most common are cigarette smoking, high blood pressure and diabetes. Endothelial dysfunction makes it difficult for the veins and arteries to properly dilate. Eventually this leads to atherosclerosis and then, heart disease.

Platelets are irregularly-shaped, colorless bodies that are present in blood. Their sticky surface lets them, along with other substances, form clots to stop bleeding. Platelet aggregation is blood clotting. We all need our platelets to have the ability to form clots to stop bleeding when we have a cut or wound. However, excess platelet aggregation in the arterial walls is a leading contributor heart disease.

Many heart attacks happen as a result of endothelial dysfunction, atherosclerosis, and blood clots (thrombosis). It works like this. Too much LDL cholesterol circulating in our blood oxidizes and turns into hard plaque, which then sticks to the arterial walls, making them narrower.

Endothelial dysfunction prevents the artery walls from dilating properly, which makes them even less able to move blood successfully to and from the heart and brain.

When arteries and veins are so narrow, and blood flow is already restricted, even the smallest clot can block an artery completely. If an artery feeding the heart becomes blocked, it can cause a heart attack. A stroke happens when an artery leading to the brain becomes blocked.

So, how do you prevent these problems from happening to you? Well, here are some steps you can take to reduce your risk of heart disease. First, don't smoke. Smoking increases blood pressure, decreases exercise tolerance and increases the tendency for blood to clot.

Secondly, watch your diet. Reduce the level of saturated fats and high cholesterol foods that you regularly consume. This includes eating less red meat, butter and fewer eggs. In particular, you should stay away anything with trans fats, as these have been shown to particularly increase endothelial dysfunction. Learn to read food labels and stay away from foods that contain anything partially hydrogenated or hydrogenated.

Thirdly, get some exercise. Doctors recommend that you spend at least 30 minutes exercising, at least 5 times a week. Walking is an excellent way to get your exercise, because you can do it anywhere, it requires no special equipment beyond a pair of shoes, and nearly anyone can do it.

So, get out your walking shoes and get going. Take it at your own pace; if you're unaccustomed to exercising, it may be tough at first. But, you can speed up your pace and duration as you gain fitness.

You might also consider weight training 3 times a week for about 20 minutes a session. Weight training can help you build muscle, which makes you stronger and helps you burn more fat. Even resting, muscle requires more calories in a day to survive, so by building muscle, you're automatically increasing the number of calories you burn in a day.

If you're overweight, lose the excess pounds. The diet and exercise guidelines above should help you significantly, but you may also need to watch your calorie intake. Take a look at the portions you're eating to ensure that you're not eating too much.

As you're evaluating and making changes to your diet, make certain that you're getting your fair share of anti-oxidants every day. Anti-oxidants are critical to preventing disease because they fight the free radicals that our bodies create each day during our digestive process. If the free radicals are not neutralized, they damage our cells and DNA, leading to disease.

Fruits and vegetables are great sources of anti-oxidants, as is dark chocolate and red wine. But the anti-oxidant source that might give you the most bang for your buck is green tea. Green tea is full of one of the most potent anti-oxidants around, and has been connected in many studies with reducing the risk of diseases, including cardiovascular disease.

Green tea, and other foods that are extremely high in anti-oxidants, have been shown to reduce the risk of heart disease in several ways. The most important are:

• Green tea has been shown to prevent circulating LDL from hardening into the plaque that sticks to arterial walls, narrowing them.

• Green tea has been shown to inhibit unnecessary platelet aggregation.

• Green tea has been shown to reverse endothelial dysfunction.

• Green tea has an anti-inflammatory effect, which may help protect arteries and blood vessels.

The benefits of green tea and other foods high in anti-oxidants for preventing heart disease are outlined in a study reported by the UK Tea Council.

As you can see, drinking green tea may be one of the easiest things you can do to prevent heart disease - and many other diseases, too. Green tea is inexpensive and easy to find. So, what are you waiting for? Grab a bottle of green tea as you head out the door for that walk!