Heart attacks are the commonest serious illnesses suffered by men and
women to-day.
Heart attacks are the result of two main processes. One is known as
‘atherosclerosis’. In this condition, there is a gradual build-up of fatty
substances in the walls of the coronary arteries which supply the heart
muscle with blood. The second is thrombosis, i.e., the development of a
clot in a coronary artery. The heart attack is often a sudden event that occurs
when a clot develops at the site of a narrowing in the artery and cuts off the 
blood supply to the muscle beyond.
We still do not know all we need to about why heart attacks occur but
we can make them much less likely by taking appropriate steps to reduce the
risk.
There are several things everyone can do to reduce the risk of a heart
attack. A useful point to remember is that all of them promote healthy living
in general and help prevent other diseases in addition to heart attacks.
If you read or listen to the media, you may have got the impression tha
doctors cannot agree about the importance of the various factors in causin
heart attacks. In fact, nearly all doctors agree that high blood cholestero
levels increase the likelihood of heart attacks and that lowering hig
cholesterol levels is helpful in preventing them. There are some differenc-
of opinion about the relative importance of the risk factors and what should
done to correct these, but the advice given in this chapter is widely accepted.