Blood pressure is the force exerted by circulating blood on the walls of arteries. It is also dependent on the response of the arteries to the flow of blood (known as arterial resistance). If the force or the resistance to blood flow is reduced, then there will be a drop in blood pressure.
Whilst there is a well known threshold blood pressure level for hypertension, there isn't really one for low blood pressure or hypotension. In general, a blood pressure level of below 90/60mmHg is considered low. Having said that, there are instances where a reading below this can be considered normal. This will be discussed shortly.
How does low blood pressure happen?
There is reduced blood flow in the arteries if there is less blood being pumped with each heart beat. This could be due to either low blood volume - as in acute blood loss or severe dehydration - or weak pumping motion of the heart - as in heart failure. If the heart beat becomes slow such as in atrial fibrillation or complete (electrical) heart block, the overall cardiac output will also be reduced thereby lowering the blood pressure.
www.mmail.com.my
0 comments:
Post a Comment