This book is principally about your heart: how to keep it strong or, if it has been weakened in some way, how to make it as strong as possible. The major cause of weakening of your heart is called coronary artery disease (CAD). The coronary arteries are those arteries which feed the heart itself. They arise from the main artery leaving the heart, the aorta, and run around the outside of the heart, sending many branches into the heart’s muscle. They deliver oxygen and energy so that the heart can do its job of pumping blood around the body. If the coronary arteries become narrowed, the blood supply to the heart will be restricted. The result is that when the heart needs to beat faster (such as when you are walking up a hill), your heart will be starved of energy and begin to complain, usually by causing chest pain (known as angina). If a coronary artery blocks completely, there will a sudden loss of blood to a portion of heart muscle, chemicals build up, you will experience severe pain and a heart attack occurs as part of the muscle stops working. If a big coronary artery blocks, the heart attack will be large; if a small artery is blocked, there will only be a small loss of muscle. Coronary disease is our greatest medical enemy and as much a threat to women as to men. Women may think of it as a man’s disease, but it is an equal opportunity killer with no respect for sex, race or religion. Coronary heart disease kills nearly 117 000 men and women in the UK each year, and in America 450 000 adults die each year of coronary artery disease; over one-third of these are women. This means that an average of 320 people a day (or one person every fourand- a half minutes) die from coronary artery disease in the UK. Women may be more afraid of breast cancer but it is more than five times as likely that they will die from the consequences of heart disease. It is so common that one in three adults of both sexes over 65 years of age has some form of heart disease.