What is a high diastolic blood pressure?

Blood pressure is the pressure of blood pushing against the walls of your arteries. Arteries carry blood from your heart to other parts of your body.

Your blood pressure normally rises and falls throughout the day.

Blood pressure is measured using two numbers:

The first number, called systolic blood pressure, measures the pressure in your arteries when your heart beats.

The second number, called diastolic blood pressure, measures the pressure in your arteries when your heart rests between beats.

If the measurement reads 120 systolic and 80 diastolic, you would say, “120 over 80,” or write, “120/80 mmHg.”

A normal blood pressure level is less than 120/80 mmHg.1

No matter your age, you can take steps each day to keep your blood pressure in a healthy range.

High blood pressure, also called hypertension, is blood pressure that is higher than normal. Your blood pressure changes throughout the day based on your activities. Having blood pressure measures consistently above normal may result in a diagnosis of high blood pressure (or hypertension).

The higher your blood pressure levels, the more risk you have for other health problems, such as heart disease, heart attack, and stroke.

Your health care team can diagnose high blood pressure and make treatment decisions by reviewing your systolic and diastolic blood pressure levels and comparing them to levels found in certain guidelines.

If an individual has hypertension, they have an increase in both systolic and diastolic blood pressure.

However, elevated diastolic blood pressure occurs in isolated diastolic hypertension (IDH). Doctors classify stage 1 IDH as a diastolic blood pressure of 80–89 mm Hg diastolic blood pressure. They classify stage 2 IDH as diastolic blood pressure above 90 mm Hg.

Learn more about blood pressure readings here.

IDH is uncommon and accounts for less than 20% of hypertension cases.

Doctors do not understand why an individual may develop diastolic hypertension. They suggest the narrowing of arterioles causes it due to hormones in the body.

Common causes of isolated diastolic hypertension are:

A study demonstrated the link between severe sleep apnea and higher diastolic blood pressure.

However, some potential and preventable causes of IDH also include the following:

Doctors usually associate hypertension with obesity. However, they also link being overweight and having obesity to IDH.

To reduce the risk of IDH, a person can take steps to reach a moderate weight through diet and exercise.

If they find it challenging to make dietary changes or increase physical activity, a doctor can suggest alternative weight management options.

Some studies show that alcohol consumption contributes to IDH.

To help prevent high blood pressure, the AHA recommends that males do not consume more than two alcoholic drinks per day and females no more than one alcoholic drink per day.

The AHA states that one drink is either:

Learn more about ways to reduce alcohol consumption here.

Research associates smoking with IDH. For example, a study in China found that among individuals age 90 and over, current or previous heavy smoking increased diastolic blood pressure.

Learn more about ways to give up smoking here.

Elevated triglycerides or blood fats are another potential cause of IDH that doctors also link to other health risks.

Almost one in three Americans have high triglycerides. When these blood fats are high, they lower ‘good’ HDL cholesterol. If individuals have elevated blood triglycerides and high ‘bad’ LDL cholesterol, this increases their risk of heart disease and stroke.

People can lower their blood triglycerides by making dietary changes. For example, following a Mediterranean-style diet rich in oily fish, fruit, vegetables, and whole grains may help reduce blood triglycerides and IDH.

Approximately 1.28 billion adults worldwide aged 30–79 have hypertension.² Hypertension is sometimes referred to as the ‘silent killer.’

Many people with hypertension have no symptoms or warning signs, so they aren’t even aware they have high blood pressure. Therefore, it's essential to have your blood pressure measured routinely, either at home with your own blood pressure cuff or at a doctor’s office.

Symptoms of high blood pressure

Typical symptoms of hypertension include:

People with severe hypertension may experience:

How blood pressure is measured

Two numbers are used to measure blood pressure:

• Limit alcohol consumption. Drinking too much alcohol can raise blood pressure to an unhealthy level.
• Limit caffeine consumption.
• Reduce sodium intake.
• Increase potassium intake.
• Limit saturated and trans fats.
• Avoid sugar.
• Eat heart-healthy foods.
• Add probiotics.

High blood pressure is when the top number (systolic pressure) is 130 or higher or the bottom number (diastolic pressure) is 80 or higher.