Low Blood Pressure: Symptoms and Causes (2024)

While there are thresholds for defining high blood pressure, there is no specific definition of low blood pressure. Instead, doctors typically consider blood pressure too low if it causes symptoms.Blood pressure measures the pressure of blood inside arteries when your heart pumps and when it is at rest. A normal blood pressure range is less than 120/80 mmHg. It is possible for people with normal blood pressure to experience symptoms if their blood pressure goes lower than 90/60 mmHg. However, low blood pressure can also be normal in healthy people with small stature and athletes. This means treatment may not be necessary.

Your blood pressure can vary based on the time of day. Low blood pressure has many possible causes.

The causes of low blood pressure include Trusted Source American Heart Association Highly respected national organization Go to source:

• prolonged bed rest
• pregnancy
• a decrease in blood volume from trauma, dehydration, or internal bleeding
• certain medications
• heart conditions
• endocrine issues
• severe infection, such as septic shock
• allergic reaction, such as anaphylaxis
• nutritional deficiencies
• neurally mediated hypertension

There are three main types of clinically significant low blood pressure.

Orthostatic hypotension occurs when your blood pressure drops when you stand up. It causes symptoms including dizziness, feeling faint, and blurred vision. It may also cause syncope, a temporary loss of consciousness.

Typically, your circulatory system can adjust to changes in position. It usually restores blood pressure quickly, although sometimes you may need to sit or lie down while recovering.

Causes of orthostatic hypotension may include:

• a lesion of the baroreflex loop
• decreased amount of blood in your body
• Addison’s disease
• certain neurological conditions, such as:
  • multiple system atrophy with orthostatic hypotension
  • autonomic system neuropathies
  • other dysautonomias

In neurally mediated hypotension, your blood pressure decreases after extended periods of standing. It may cause dizziness, faintness, and nausea. This type of low blood pressure is the result of abnormal signaling of the brain and nerves. It is most common Trusted Source American Heart Association Highly respected national organization Go to source in children and young adults and typically resolves over time.

Low blood pressure linked to shock is a serious condition Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source that interferes with blood flow to your vital organs. The drop in blood pressure is more severe than in orthostatic hypotension or neurally mediated hypotension. It does not typically improve when you lie down. Shock is often due to:

• significant blood loss
• severe allergic reactions
• serious infections
• large burns
• poisoning

Shock is considered a life threatening condition. If you or someone you know is experiencing symptoms of shock, seek immediate medical care.

Symptoms of shock include:

• hypotension
• rapid heart rate or tachycardia
• rapid breathing
• change in the level of alertness
• change in mental status
• cold and clammy skin
• mottled skin
• decreased urination

Learn what blood pressure readings mean.

Low blood pressure does not always cause symptoms. Sometimes, it is discovered only during a routine examination. However, doctors typically consider Trusted Source American Heart Association Highly respected national organization Go to source low blood pressure dangerous only if it causes symptoms.

Symptoms of low blood pressure may include:

• nausea
• dizziness or lightheadedness
• fainting
• unusual thirst
• lack of concentration
• blurred vision
• cold, clammy, or pale skin
• rapid or shallow breathing
• fatigue
• depression
• weakness or tiredness
• heart palpitations

If you are experiencing any of these symptoms, contact your doctor.

Low blood pressure does not always require treatment. Sometimes, treating the underlying cause of decreased blood pressure can raise your levels.

Your doctor may recommend changing the dose of medications or wearing support socks to help with your circulation.

They may also recommend lifestyle changes, such as:

• moving slowly when standing or sitting up
• eating small and frequent meals
• lying down or sitting still after a meal
• drinking plenty of water to stay hydrated
• not sitting or standing for long periods
• not changing posture or bending suddenly
• not drinking caffeinated drinks at night
• not drinking too much alcohol
• avoiding hot showers

Learn about blood pressure monitoring.

Low blood pressure is often considered any level under 90/60 mmHg. It does not always cause symptoms. Sometimes, lower blood pressure is a normal level for some people.

Doctors do not typically consider low blood pressure an issue unless it causes symptoms. If you are experiencing symptoms, treatment may include changing doses of medications, treating underlying conditions, and lifestyle changes.

A life threatening cause of low blood pressure is shock. If you or someone you know is experiencing symptoms of shock, seek immediate medical care.