Chronic high blood pressure is a serious disorder, while chronic low blood pressure (lower than normal) is almost never a problem. Low blood pressure occurs abruptly and causes dizziness or unconsciousness.
The most common form is a phenomenon known as postural (orthostatic) hypotension. When you jump from a sitting or lying position, your blood vessels must be assembled to maintain normal blood pressure in a new body position, and this process is carried out automatically by a reflexive action of the nervous system.
But, if you have postural hypotension, this reflex action is in some way disrupted. The consequence of this is a decrease in pressure, so blood flow to the brain temporarily decreases with a sudden change in body position; this causes dizziness or even a short loss of consciousness.
Postural hypotension usually occurs due to overdose of some antihypertensive agents. They act on a nervous system which, if the dose is too high, can cause postural hypotension. It is treated simply – by reducing the dose. Sometimes, postural hypotension occurs as a complication in pregnancy or some sickness conditions (such as diabetes or arteriosclerosis).
Sometimes, low blood pressure reduces the blood flow to the brain so much that the person, to whom it happens, will faint. This can happen due to illness or because of a physical reaction to sudden excitement, malnutrition or long standing in the heat. There is no need to be worried about those occasional fainting, caused by low blood pressure.
What to do?
If you are dizzy, or you feel like you could faint when you get up suddenly, try to lift slowly from the sitting or lying position. If this is a re-occuring problem, contact a doctor who will measure your blood pressure and possibly refer you to diagnostic tests to find out the main problem. However, special treatment of long-lasting hypotension is usually not necessary.