Most of us are aware of heart attack symptoms such as chest pain or shortness of breath.
But a recent study indicates that 'silent' heart attacks, which occur without symptoms, may be far more common than many people realise.
In fact, a new release by the American Heart Association founds that as many as half of all heart attacks may be 'silent.'
A senior author of the study says: "The outcome of a silent heart attack is as bad as a heart attack that is recognised while it is happening... And because patients don't know they have had a silent heart attack, they may not receive the treatment they need to prevent another one."
Of the 9,498 middle-age adults who were observed as part of the study over an average of nine years, 317 had silent heart attacks and 385 had heart attacks with clinical symptoms.
The team involved in the study recommends that the treatment of both types of heart attacks should be similar. ""Doctors need to help patients who have had a silent heart attack quit smoking, reduce their weight, control cholesterol and blood pressure and get more exercise," they say.