Low blood pressure (hypotension)

Low blood pressure (hypotension) would seem to be something to strive for. However, for many people, low blood pressure can cause symptoms of dizziness and fainting. In severe cases, low blood pressure can be life-threatening.

Although blood pressure varies from person to person, a blood pressure reading of 90 millimeters of mercury (mm Hg) or less systolic blood pressure (the top number in a blood pressure reading) or 60 mm Hg or less diastolic blood pressure (the bottom number) is generally considered low blood pressure.

The causes of low blood pressure can range from dehydration to serious medical or surgical disorders. Low blood pressure is treatable, but it's important to find out what's causing your condition so that it can be properly treated.

Symptoms Causes Risk factors Complications

For some people, low blood pressure can signal an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:

  • Dizziness or lightheadedness
  • Fainting (syncope)
  • Lack of concentration
  • Blurred vision
  • Nausea
  • Cold, clammy, pale skin
  • Rapid, shallow breathing
  • Fatigue
  • Depression
  • Thirst

When to see a doctor

In many instances, low blood pressure isn't serious. If you have consistently low readings but feel fine, your doctor is likely to monitor you during routine exams.

Even occasional dizziness or lightheadedness may be a relatively minor problem — the result of mild dehydration from too much time in the sun or a hot tub, for example. In these situations, it's not a matter so much of how far, but of how quickly, your blood pressure drops.

Still, it's important to see your doctor if you experience any signs or symptoms of hypotension because they sometimes can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you were doing at the time.

© 1998-2015 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of use