Low blood pressure might seem desirable, and for some people, it causes no problems. However, for many people, abnormally low blood pressure (hypotension) can cause dizziness and fainting. In severe cases, low blood pressure can be life-threatening.

A blood pressure reading lower than 90 millimeters of mercury (mm Hg) for the top number (systolic) or 60 mm Hg for the bottom number (diastolic) is generally considered low blood pressure.

The causes of low blood pressure can range from dehydration to serious medical or surgical disorders. It's important to find out what's causing your low blood pressure so that it can be treated.

Aug. 11, 2017
  1. Hypotension. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/book/export/html/4880. Accessed Dec. 11, 2016.
  2. Low blood pressure. American Heart Association. http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/AboutHighBloodPressure/Low-Blood-Pressure_UCM_301785_Article.jsp. Accessed Dec. 11, 2016.
  3. Kaufman H, et al. Mechanisms, causes and evaluation of orthostatic hypotension. http://www.uptodate.com/home. Accessed Dec. 11, 2016.
  4. Understanding blood pressure readings. American Heart Association. http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/AboutHighBloodPressure/Understanding-Blood-Pressure-Readings_UCM_301764_Article.jsp. Accessed Dec. 11, 2016.
  5. Kaplan NM, et al. Ambulatory and home blood pressure monitoring and white coat hypertension. http://www.uptodate.com/home. Accessed Dec. 13, 2016.
  6. Kaufman H, et al. Treatment of orthostatic and postprandial hypotension. http://www.uptodate.com/home. Accessed Dec. 11, 2016.