Question

Can one's blood pressure be too low? My blood pressure is normally in the 90/60 area, but once it was 86/54 and I was given the impression that when it goes below 90/55 that is too low.

Answer

Low blood pressure is called hypotension. There are many different causes of hypotension (see below), including medicines (e.g. an overdose of a drug used to treat high blood pressure). Some people experience a temporary fall in blood pressure when getting up from a horizontal position or standing up quickly (postural, or orthostatic hypotension). Postural hypotension can follow prolonged bed rest or rehabilitation following acute illness.

In general, the lower your blood pressure, the better - unless you have symptoms of hypotension. These may be weakness, dizziness, tiredness, or perhaps even fainting. Many people can function well with a low blood pressure, and it's only if you are getting adverse symptoms that it becomes a problem. In this case, it would be important to report these symptoms to a doctor and have the reason investigated.

Some of the possible causes the doctor will want to consider include:

- certain nervous system disorders (e.g. postural hypotension)

- endocrine, or glandular, disorders (e.g. parathyroid disease)

- heart attack

- prolonged bed rest

- fainting (syncope)

- decreases in blood volume due to severe bleeding (hemorrhage) or dehydration (medical shock)

- effects of certain drugs

- severe infections (sepsis)

Links

• AHA: Low Blood Pressure
• MedlinePLUS: Low Blood Pressure