Hypotension (Low Blood Pressure)

By Ashley Henshaw. May 7th 2016

While most people are familiar with hypertension, they may fail to recognize that hypotension can be just as serious a condition. Fortunately, low blood pressure is treatable and can be easily recognized by key signs and symptoms.


Low blood pressure, also known as hypotension, occurs when blood pressure drops below a normal range. Though it varies from person to person, a reading of 90 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 in a blood pressure reading) is generally considered to be hypotension. Low blood pressure is often an indicator of an underlying problem and is especially dangerous when the blood pressure drops suddenly.


There are four main types of hypotension:

  • Postural or orthostatic hypotension: This is low blood pressure which occurs when you stand up from sitting down or lying down.
  • Postprandial hypotension: This occurs when blood pressure drops suddenly after eating.
  • Neurally mediated hypotension: This occurs when blood pressure drops after standing for long periods of time.
  • Multiple system atrophy with orthostatic hypotension: This is also known as Shy-Drager syndrome. Marked by progressive damage to the autonomic nervous system, this condition causes hypotension when standing and hypertension when lying down.

Those these categories may be used to help define a person’s condition, they may not account for all cases of hypotension.


There are many signs and symptoms which may appear when a person has low blood pressure, including:

  • Dizziness
  • Lightheadedness
  • Fainting
  • Fatigue
  • Nausea
  • Thirst
  • Rapid, shallow breathing
  • Cold, clammy, pale skin
  • Blurred vision
  • Depression

Causes And Risk Factors

Several medical conditions are considered to be possible causes of low blood pressure. Those causes include:

  • Pregnancy: Pregnant women often experience hypotension because their circulatory system is rapidly expanding during their pregnancy.  Their blood pressure typically returns to a normal level once they give birth.
  • Dehydration: Even mild cases of dehydration can cause low blood pressure. Dehydration can result from having a fever, vomiting, strenuous exercise, overuse of diuretics or severe diarrhea.
  • Poor diet: It’s important to get enough of the vitamins B-12 and folate in your diet to avoid anemia, which causes low blood pressure
  • Heart problems: Heart valve problems, low heart rate, heart attack and heart failure can all lead to hypotension. The problem usually lies in the heart’s failure to circulate enough blood.
  • Blood loss: A major injury or internal bleeding reduce the amount of blood in the body and results in a severe drop in blood pressure.
  • Severe allergic reactions: Also known as anaphylaxis, a severe allergic reaction can cause blood pressure to drop suddenly.
  • Severe infection: Also known as septicemia, any infection that enters the bloodstream can cause potentially fatal drops in blood pressure.
  • Endocrine problems: An under- or overactive thyroid can trigger hypotension.
  • Hypovolemic shock: This is a dangerous condition which may result from severe dehydration. It occurs when a person has low blood volume and can cause a potentially fatal sudden drop in blood pressure.
  • Taking certain medications: Diuretics, beta blockers, alpha blockers, certain antidepressants, Viagra and drugs for Parkinson’s disease could potentially cause hypotension.

Hypotension can affect anyone, but those who are over the age of 65 are more likely to experience this condition. In addition taking any of the medications listed above can increase a person’s risk for low blood pressure. Certain diseases, including heart conditions, diabetes and Parkinson’s disease, also come with an increase risk of hypotension.


Not all cases of hypotension are preventable, but taking the following steps can reduce your risk of developing the condition:

  • Drink water: Drinking water helps combat dehydration and increases blood volume. In addition, avoid dehydrating drinks like alcohol.
  • Eat healthy: Make sure your diet is rich in nutrients, including vitamins B-12 and folate. In addition, eat small portions and limit high-carb foods in order to avoid blood pressure dropping suddenly after meals.
  • Change body positions slowly: Slowly sit up and breathe deeply as you get out of bed in the morning or standing up from a sitting position.


In some cases, the symptoms of hypotension may be very mild and may not signal the need for immediate medical attention. However, it’s still important to see a doctor if you do experience these symptoms (regardless of their severity) since low blood pressure can be an indicator of a more serious health condition.

For those who have consistently low blood pressure that is not caused by underlying problems, most doctors will simply advise that you have your blood pressure checked regularly through routine exams. In some cases, patients may be asked to keep a record of how often they experience the symptoms of low blood pressure and what they were doing at the time that the symptoms occurred.

For more serious cases of hypotension, the underlying cause is treated first, whether it’s endocrine problems, heart problems or dehydration. In addition, a doctor may help you find other medications if the ones you are taking are causing hypotension.

In some cases, chronic low blood pressure may appear to have no underlying cause. Doctors may treat these conditions by recommending certain treatments, such as drinking more water, wearing compression stockings or adding more salt to the diet. In addition, there are some medications available to help treat low blood pressure that occurs when standing up.

Low blood pressure is not always a serious condition, but it is vital that you make an appointment to see a doctor if you are experiencing the symptoms of this condition. It is often very treatable and can alert you to other health conditions you may not have been aware of.


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