Coronary heart disease is caused by the build-up of artherosclerosis, [fatty deposits] or plaque on the inside of artery walls. This narrows the channel inside the artery so there is less room for the blood to flow through.

The following 2 critical risk factors you should be aware of if you wish to avoid a heart attack or heart disease.

SMOKING.

Stopping smoking is the single most important thing you can do to reduce your risk of heart disease, according to the Heart Foundation.

Smoking reduces the amount of oxygen in your blood, damages and constricts your artery walls and increases blood pressure. It also increases your heart rate, and can increase the rate at which cholesterol deposits accumulate in the blood vessels.

For many smokers, fear is a major factor. Fear of giving up the pleasure or the crutch, fear that you will be unable to enjoy life or handle stress. A number of strategies are available. These include patches as well as psychotherapy and hypnotherapy.

The benefits of quitting however, are almost immediate. From the moment you stop smoking, your extra risk of heart disease begins to decrease. One year after stopping, your risk of another heart attack is around half that of a continuing smoker.

LACK OF PHYSICAL ACTIVITY.

Your body is designed to move.Therefore regular moderate physical activity is good for your heart. Being active can be fun, make you feel good in yourself and help boost your immune system. Physical activity can also help control other risk factors such as blood pressure and weight.

The Heart Foundation recommends 30 minutes or more of physical activity [such as brisk walking] on most days of the week. If you don't have time for a 30 minute block, take three 10 minute walks and accumulate in shorter bouts.

Walking 19km a week is enough exercise to improve cardiovascular health, according to a US study published in the October 2005 issue of the journal Chest.

Researchers at Duke University Medical Centre found that overweight people who walked 19km a week, considered by the scientists to be a "moderate" amount of exercise, consumed oxygen more efficiently and gained physical endurance, both of which reduced the risk of heart disease.

The most important factor is to pace yourself. If you have difficulty talking after exercise, you may be over exerting. A good test for this is the target heart rate for your age and this is calculated by using a heart rate monitor.

A heart rate monitor is a good way to measure the intensity and quality of your workouts and maximise your outcomes. You use percentages of you maximum heart rate [MHR] to judge the intensity for you. To work out your MHR you simply deduct your age from 220. About 50 to 60 percent of your MHR is a good level for improving your overall health. Once you hit 60 to 70 percent, you're in the "fitness zone" This is perfect for those looking to train at a moderate intensity.

Seventy to 85 percent is about the fastest pace at which you can exercise and still talk. This is great for runners wanting to improve performance. Don't go higher than this, 85 to 100 percent is a zone best reserved for serious athletes with a high pain tolerance.