You may develop low diastolic blood pressure due to certain medications or aging. You can also have low diastolic blood pressure if you have low blood pressure overall.

The medical term for low blood pressure is hypotension. If you have hypotension, your systolic pressure measurement is under 90 millimeters of mercury (mm Hg) and your diastolic number is under 60 mm Hg.

Some people can have low diastolic pressure even when their systolic pressure is considered normal. This condition is called isolated diastolic hypotension.

Unlike the rest of your body, which receives blood when your heart pumps, the muscles of your heart receive blood when your heart relaxes.

If your diastolic blood pressure is too low, your heart muscles won’t get enough oxygenated blood. This can lead to the weakening of your heart, a condition called diastolic heart failure.

What does blood pressure measure?

Your blood pressure is the force inside your blood vessels when your heart beats and relaxes. This force is measured in mm Hg and is represented as two numbers.

The upper number, called your systolic pressure, is measured when your heart beats. The lower number, called your diastolic pressure, is measured when your heart relaxes between beats.

You may have low diastolic blood pressure if you take specific medications or due to aging. You can also have low diastolic blood pressure if you have low blood pressure in general (hypotension). Treatment for low diastolic blood pressure largely depends on the type of hypotension.

Isolated diastolic hypotension

There are a few known causes of isolated diastolic hypotension.

Medications

Alpha-blocker medications are blood pressure medications that work by causing your blood vessels to open up, or dilate. Because they lower diastolic pressure more than systolic pressure, they may cause isolated diastolic hypotension.

Common brand names include prazosin (Minipress) and doxazosin (Cardura).

If you’re taking an alpha-blocker and have low diastolic blood pressure, a doctor can prescribe a different high blood pressure medication.

Aging

As we age, we lose the elasticity of our arteries. For some older adults, the arteries may become too stiff to spring back between heartbeats, causing low diastolic blood pressure.

If you have isolated low diastolic pressure and you’re not on blood pressure medication, the only option may be to see your doctor more frequently for checkups and to watch for symptoms of heart failure.

Currently, there’s no medication available to treat isolated diastolic hypotension.

Overall low blood pressure

There are several common causes of overall hypotension, which would include a low diastolic number. Treatment of general hypotension depends on the cause.

Medications

For some people, especially people over age 60, lowering systolic blood pressure below 120 with medication may cause diastolic pressure to fall below 60. This is considered overtreatment of high blood pressure.

Overtreatment of high blood pressure can be managed by adjusting or changing medications. The goal is to keep the diastolic blood pressure between 60 and 90 mm Hg.

Many medications besides those for blood pressure can cause hypotension. They include:

A doctor may also change other medications that cause hypotension.

Heart conditions

Some heart problems can cause hypotension. These can include:

If you have one of these medical conditions, treating it may help raise your blood pressure to normal levels.

Dehydration

Dehydration can also cause hypotension.

If you don’t take in enough fluids, your blood pressure can become dangerously low. This may happen if you’re taking a diuretic and lose more fluids than you take in.

Dehydration can be treated with fluid replacement. In some cases, you may need medications that increase blood pressure.

Other causes

Some people may experience low blood pressure due to:

  • neurally mediated hypotension, which causes low blood pressure if you stand for a prolonged time
  • position changes, such as lying down or sitting and then standing up, which can temporarily cause blood pressure to drop
  • diabetes
  • anemia
  • alcohol use, especially while taking some medications
  • pregnancy
  • blood loss

Symptoms of isolated diastolic hypotension include:

  • tiredness
  • dizziness
  • falls

Because low diastolic pressure decreases blood flow to your heart, you may also have chest pain (angina) or symptoms of heart failure, including:

  • shortness of breath
  • swelling of your feet or ankles
  • confusion
  • heart palpitations
Medical emergency

Call 911 and go to the nearest emergency room if you have chest pain or difficulty breathing.

Symptoms of hypotension

If you have low diastolic blood pressure along with low systolic blood pressure (hypotension), you may experience additional symptoms. Symptoms of hypotension include:

  • dizziness
  • fainting (syncope)
  • frequent falls
  • tiredness
  • nausea
  • blurred vision

You may need medical attention if you have any of these symptoms.

Low diastolic blood pressure doesn’t always lead to a larger health concern. But in some cases, the effects of low diastolic blood pressure may be long lasting and potentially life threatening.

Complications of low diastolic blood pressure include:

Risk of injury from falls

If your blood pressure is low enough, it can cause symptoms such as fainting or dizziness.

This causes a significant risk of falling. This can lead to serious injuries, such as head trauma.

Heart tissue damage and heart disease

Researchers have found a link between low diastolic blood pressure and heart damage.

A 2020 study found that low diastolic blood pressure and some cardiac issues, such as stroke, heart attack, and heart failure, may have a correlation.

A 2023 study suggests that health conditions such as diabetes that may cause initial high blood pressure can ultimately cause low diastolic blood pressure. This is because the inflammation causes vascular injury and the blood vessel walls become damaged due to high blood pressure. This damage can lead to heart failure.

Some things you can do to help prevent and manage low diastolic pressure may include:

  • Try to keep your salt intake to around 1,500–2,300 milligrams per day, according to the American Heart Association. Read food labels to avoid added salt in your diet.
  • Eat a heart-healthy diet. This includes eating plenty of fruits, vegetables, whole grains, and lean protein.
  • Drink enough fluids and avoid alcohol, which can increase your risk of dehydration.
  • Stay physically active with an exercise program. A doctor can determine what type and amount of exercise is safe for you.
  • Maintain a moderate weight. If you are looking to lose weight, a doctor can help you create a safe weight loss plan.
  • If you smoke, consider reaching out for support to quit.

What is the lowest acceptable diastolic blood pressure?

Low diastolic blood pressure is 60 mm Hg or lower. If your blood pressure is 90/60 mm Hg or lower, doctors consider you to have low blood pressure.

What causes a low diastolic pressure?

Low diastolic blood pressure tends to occur as a result of taking medication for high blood pressure. It may also happen due to aging and other medical conditions.

How do you treat low diastolic blood pressure?

If you have low diastolic blood pressure and take an alpha-blocker, doctors may switch your blood pressure medication to another one.

What heart problems cause low diastolic blood pressure?

People with certain heart conditions may be more likely to develop low blood pressure (low systolic and low diastolic blood pressure). These can include heart valve problems, heart failure, and a slow heart rate (bradycardia).

Hypotension can be dangerous because it’s a frequent cause of falls. Isolated diastolic hypotension can decrease blood flow to your heart. Over time, isolated diastolic hypotension can potentially lead to heart failure.

Pay attention to your diastolic number when you have your blood pressure checked. If your lower number is 60 mm Hg or below, ask a healthcare professional about it.

Let a doctor know if you have any symptoms of hypotension or heart failure. In many cases, switching medications along with making lifestyle changes can help. A doctor may want to follow you more closely to ensure your diastolic pressure stays above 60 mm Hg.