High diastolic blood pressure is a type of hypertension. Doctors do not know exactly why it happens, but obesity, high triglyceride levels, smoking, and alcohol may all contribute. Medication and lifestyle choices can often help manage it.

Doctors describe blood pressure using two numbers: systolic and diastolic. They present a reading with the systolic number appearing above the diastolic. Systolic measures the pressure during the heart’s contraction, while diastolic is the pressure in the period between heartbeats.

The American Heart Association (AHA) states that people put a lot of emphasis on the systolic number. However, each increase of 10 millimeters of mercury (mm Hg) in diastolic pressure among 40–89 doubles the risk of heart disease or stroke.

Doctors define isolated diastolic hypertension (IDH) — high diastolic blood pressure — as above 80 mm Hg in individuals with normal systolic blood pressure.

This article discusses the common causes of high diastolic blood pressure and the risks associated with it, how to prevent high blood pressure, and the treatment options.

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:

Obesity

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.

Alcohol consumption

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:

  • 12 ounces (oz) of beer
  • 4 oz of wine
  • 1.5 oz of 80-proof spirits
  • 1 oz of 100-proof spirits

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.

There are certain risk factors for high diastolic blood pressure that a person cannot control.

They include:

  • Age: Diastolic hypertension is common in people under 50 years of age. IDH is rare in senior adults.
  • Family history: Having family members with hypertension increases an individual’s risk of IDH.
  • Cardiovascular events: If an individual has experienced an incident that damaged the heart muscle, this increases their risk of IDH.
  • Diabetes: People with diabetes and raised blood sugar levels may be more likely to develop IDH.
  • Hypothyroidism: Around 30% of individuals with low thyroid hormone levels have IDH.
  • Kidney disease: Individuals with chronic kidney disease may also have IDH.
  • Biological sex: In a large 2019 study of almost 2.5 million participants, researchers found that the prevalence of IDH was significantly higher for males at 4.5% of the overall population compared to females at 2.2%.

If an individual has normal systolic blood pressure, lowering the diastolic blood pressure can affect the brain’s blood flow regulation, leading to a stroke.

According to a study, researchers associated IDH with an increased risk of subsequent cardiovascular events.

IDH increases an individual’s risk of various health conditions, including:

Often, elevated diastolic blood pressure does not cause notable symptoms.

A large 2019 study found that many people were unaware they had IDH. Out of 2,351,035 participants, 3.2% had IDH. Over 86% were untreated, and only 10.3% of these individuals were aware they had elevated blood pressure.

The AHA notes that the common belief that high blood pressure will cause sweating, facial flushing, or a feeling of nervousness is a myth.

However, a person should seek emergency medical attention if they experience the following symptoms. These could indicate a serious complication of IDH, such as a heart attack or stroke:

  • chest pain
  • breathing difficulties
  • lightheadedness
  • sudden onset of weakness
  • speech changes
  • loss of consciousness

Reducing diastolic blood pressure may cause heart problems, particularly in young individuals with normal systolic blood pressure. Therefore in this group, doctors may opt not to treat IDH.

IDH is uncommon in senior individuals, but doctors may choose a nonsurgical approach if present. The best approach is for doctors to treat older individuals depending on their specific underlying cardiovascular disease.

Medication options for IDH include:

Doctors may also recommend that individuals make lifestyle changes to reduce their IDH, including:

  • reducing alcohol consumption
  • maintaining a moderate weight
  • exercising daily or most days
  • eating a balanced diet
  • avoiding tobacco
  • monitoring blood pressure levels at home

Some people may be able to prevent high diastolic blood pressure from occurring by avoiding smoking, alcohol, reducing blood fats, and maintaining a moderate weight.

In other cases, some uncontrollable factors — such as biological sex, family history, and living with diabetes — may mean someone cannot prevent high diastolic blood pressure.

A lack of research suggests that anxiety triggers increases in diastolic blood pressure alone. However, anxiety may elevate diastolic blood pressure in some people.

The authors of a 2016 study state that more research is necessary to understand exactly how anxiety raises blood pressure and why it only happens in some people, especially in young adults.

One suggestion is that mental stress may activate a particular part of the nervous system that triggers a cascade of hormones, interfering with regulating blood pressure.

If a person monitors their blood pressure at home and does not see lower readings despite implementing lifestyle changes, they should contact a medical professional. Doctors can help to determine the underlying cause of their high blood pressure.

A person should seek immediate medical attention if they have two readings of 180/120 mm Hg or higher within 5 minutes, especially if they are experiencing a headache or nosebleed.

Doctors do not associate increased diastolic blood pressure with cardiovascular events in younger individuals.

However, increases in diastolic pressure in those aged 40–89 raise the risk of heart disease and stroke. Therefore, individuals should work with a doctor to find suitable treatment options and improve their outlook.

Diastolic pressure is the bottom number of a blood pressure reading.

IDH occurs if someone has elevated diastolic blood pressure, increasing a person’s risk of heart disease and stroke.

Smoking, consuming alcohol, obesity, and high blood fat may lead to IDH. Additionally, certain groups of people have an increased risk of IDH, including younger males and people with diabetes or previous cardiovascular events.

High diastolic blood pressure is rare in younger people, and doctors may not treat this group. They may recommend treatment in older individuals based on their current heart health status.

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