Does low blood pressure cause symptoms?

You may have inquired about low blood pressure because you have had one or more readings that seem abnormally low or most commonly are having symptoms, which you think might be due to low pressure. Also you may be just curious about it. That's good, everyone should be.

The body can be expected to regulate its pressure within a narrow range according to the current circumstances and what is happening at any given time. (See Normal Blood Pressure for further discussion of regulation.) The regulatory mechanisms consist of:

• Changing the amount of blood pumped by the heart (cardiac output). Rapid response.
• Varying the size of the small veins or small arteries. Rapid response.
• Changing the amount of blood in the system. Slow response.

These mechanisms are called into play by special cells, called baroreceptors, located in the walls of the large arteries. They quickly send signals to the heart, blood vessel walls and the kidneys to raise or lower pressure appropriately. There is of course a limit to the compensation ability and when it is exceeded, problems occur.

In the case of low pressure the resulting problem is usually inadequate circulation to some part of the body and this gives rise to immediate symptoms. See Symptoms of Low Blood Pressure This is in contrast to high blood pressure, which usually does not cause symptoms. See High Blood Pressure

The fact that low pressure usually causes symptoms and that high blood pressure usually does not is important. Also the symptoms are related to which part of the body is getting inadequate circulation. The most sensitive part of the body to inadequate circulation is the brain.

How does low pressure occur? Almost always it is caused by disease states. This is important. Low pressure almost always has a cause whereas high pressure usually does not.

Low pressure occurs when…

• A disorder interferes with the heart's ability to pump more blood or respond to signals for change.
• A disorder influences the veins and arteries to inappropriately constrict or dilate.
• A disorder influences the kidney to change the amount of fluid in the vascular system.

The treatment consists of identifying and correcting the underlying disorder.

Doctor's Practical Guide:

You might think of it this way: High blood pressure causes no symptoms and is called the "silent killer". Low blood pressure has symptoms thus alerting you that there is a problem.

Consider this: Low blood pressure is caused by a disorder so you get the symptoms of that disorder but also the symptoms of the low pressure itself! This produces a confusing array of symptoms to say the least. Don't get bogged down in trying to diagnose yourself. If you are having symptoms please see your doctor ASAP. It's hard enough for us to sort these out. Remember what they taught us in medical school: "Those who doctor themselves have a fool for a doctor and a fool for a patient."

Also remember that the best way to really know your blood pressure for sure is to take it yourself. See How to Take Blood Pressure

Return to the Homepage. Follow low blood pressure with High Blood Pressure