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Low blood pressure

Published: February 2020

What is low blood pressure?

Many people have naturally low blood pressure, and it’s often a sign of good health. Doctors call this chronic asymptomatic hypotension.

Sometimes, though, your blood pressure may remain consistently low, or drop suddenly. This may be a cause for concern, especially if you usually have high blood pressure.

Low pressure, also known as hypotension, is defined as below 90/60. In the worst cases, it can reduce the supply of blood and nutrients to your brain and cause potentially dangerous shock.

Low blood pressure is common during pregnancy. This usually resolves itself after the baby is born.

Types of low blood pressure

There are three main types of abnormally low blood pressure:

Orthostatic hypotension

This happens when you stand up from a seated or reclining position. When you do this, your body may not adjust quickly enough to the change, and the blood flow may be reduced, causing a drop in blood pressure. You may feel dizzy or lightheaded, but this usually goes away in a minute or two.

This condition is particularly common in older people, and those in poor health. It may be a symptom of some other medical problem.

Neurally mediated hypotension

This is caused by a change in the activity of the central nervous system, and occurs when you’ve been standing for a long time. It’s most common among children and young people, and may cause dizziness, nausea, and fainting.

Severe shock-related hypotension

Shock is a dangerous condition in which your brain and other organs receive an inadequate blood supply and are unable to function properly. Your blood pressure may fall to a very low level.

Among the most common causes of shock are blood loss, heart problems, allergic reactions, infection, and damage to the nervous system.

Symptoms and diagnosis of low blood pressure

The symptoms of hypotension vary a great deal from one case to another. They include:

  • Dizziness
  • Nausea
  • Weakness
  • Fatigue and sleepiness
  • Fainting
  • Rapid heartbeat
  • Confusion and inability to concentrate
  • Blurry vision
  • Pale, clammy skin

If your doctor believes your low blood pressure may be a sign of an underlying condition, he or she may monitor it over a longer period of time, and possibly ask you to use a home blood pressure monitor.
The diagnostic process may also include blood tests to assess your overall health, an electrocardiogram or echocardiogram, and a stress test to evaluate your heart’s performance during strenuous exercise.

Treatment

Many cases of low blood pressure can be managed by lifestyle changes. Depending on the cause, these may include:

  • Increasing your salt intake
  • Drinking lots of fluids
  • Cutting down on alcohol
  • Exercising regularly to strengthen your heart and promote blood flow
  • Avoiding sudden movements, and not standing for long periods
  • Wearing support stockings to increase blood flow

Other incidences may require medication. One of the most common is fludrocortisone, which encourages your kidneys to retain sodium, increasing your fluid retention and thus your blood pressure. Another is midodrine, which constricts your veins and arteries to achieve the same effect.


References:

www.everydayhealth.com/hypertension/when-is-low-blood-pressure-too-low/

www.nhlbi.nih.gov/health-topics/hypotension

www.patientslikeme.com/conditions/453-neurally-mediated-hypotension

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