A Guide to Low Blood Pressure (Hypotension)

What is low blood pressure (hypotension)?

Low blood pressure, also known as hypotension, is a medical condition where the pressure of blood in the arteries is consistently lower than normal. It is seen as the opposite of hypertension.

A blood pressure reading of <90/<60 is generally described as hypotension.

When the condition is chronic, it can lead to a poor quality of life and other symptoms.

Types of hypotension

Orthostatic hypotension (also known as postural hypotension) occurs when there is a change in body position, such as standing up suddenly after a prolonged state of sitting or lying down. This form of hypotension is often momentary and normal blood flow returns fairly quickly.
Postprandial hypotension happens after eating substantial meals. This is due to increased blood flow towards the intestines to allow the food to digest.
Neurally mediated hypotension (NMH) occurs from a prolonged state of standing. It can cause dizziness, fainting, or nausea.

What are the symptoms?

Unlike hypertension, there are many symptoms of hypotension. The most common symptoms are lightheadedness and dizziness but others include:

Lightheadedness, dizziness
Loss of consciousness
Extreme fatigue
Blurry vision
Feeling weak
Confusion
Nausea
Cold, clammy skin

Causes

The known causes of low blood pressure can be broken down into two categories:

Medical conditions
Medication
Pregnancy

Medical conditions that can cause low blood pressure

Dehydration
Diabetes
Heart conditions such as:
Bradycardia (low heart rate)
Valvular heart disease
Post–cardiac arrest syndrome
Endocrine conditions such as:
Parathyroid disease
Addison’s disease
Hypoglycemia (low blood sugar)
Carcinoid syndrome
Diabetic dysautonomia
Excessive blood loss
Septicemia, leading to septic shock.
Anaphylaxis
Malnutrition
Anaemia (low iron levels in the blood)
Vitamin deficiencies
Neurological conditions such as Shy-Drager syndrome (a rare condition with Parkinson’s-like symptoms)

Medication that can cause low blood pressure

Any medication taken for high blood pressure
Opioids
Parkinson’s disease medication
Tricyclic antidepressants
Erectile dysfunction medication

Pregnancy

Pregnancy is a unique cause of hypotension. As the baby grows, a pregnant person’s circulatory system expands rapidly and it can lower their blood pressure. This usually occurs in the first 2 trimesters of pregnancy. After delivery, the blood pressure should return to normal.
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Treatments and management

Treatments for low blood pressure can vary and should target the underlying cause of low blood pressure, but the primary forms of treatment for low blood pressure can be split into two categories:

Lifestyle changes
Medication

Lifestyle changes

There are different things you can change in your day-to-day life that can help manage low blood pressure, and should be undertaken after consultation with a medical provider. These include:

Changes in diet
Taking care when getting up from sitting/lying down
Staying hydrated
Reducing alcohol intake
Wearing compression stockings

Please note: These lifestyle changes can vary in the time it takes to reduce hypotension so always speak to a doctor about your particular circumstances.

Read more: How to Lower Blood Pressure

Medication that can reduce low blood pressure

There are some medications that can raise the blood pressure purposely, but should only be used under the direction of a medical provider, after checking for all reversible causes of low blood pressure.

Consult your doctor on the different medications you can take to increase your blood pressure.

Additional questions

Is low blood pressure hereditary?

Low blood pressure is not usually a hereditary condition. According to NHS Inform, some research suggests that some types of hypotension is genetic. One study by a research team in the US also found that people who inherited 2 defective copies of particular salt-regulating genes developed a rare disease—such as Gitelman or Bartter syndrome— which led to “dangerously low blood pressure”.