Low blood pressure is an abnormal condition in which a person's blood pressure (the pressure of the blood against the walls of the blood vessels during and after each beat of the heart) is much lower than usual. It can cause symptoms such as dizziness or lightheadedness.
Hypotension; Low blood pressure
When the blood pressure is too low, there is inadequate blood flow to the heart, brain, and other vital organs.
A blood pressure level that is borderline low for one person may be normal for another. The most important factor is how the blood pressure changes from the normal condition. Most normal blood pressures fall in the range of 90/60 mm Hg to 130/80 mm Hg, but a significant change, even as little as 20 mm Hg, can cause problems for some people.
Low blood pressure is commonly caused by drugs such as:
- Medications used for surgery
- Anti-anxiety agents
- Treatment for high blood pressure or coronary heart disease (CHD)
- Heart medicines
- Some antidepressants
- Narcotic analgesics
Other causes of low blood pressure include:
- Heart failure
- Heart attack
- Changes in heart rhythm (arrhythmias)
- Anaphylaxis (a life-threatening allergic response)
- Shock (from severe infection, stroke, anaphylaxis, major trauma, or heart attack)
- Advanced diabetes
Another common type of low blood pressure is orthostatic hypotension, which is brought on by a sudden change in body position, usually when shifting from lying down to standing upright.