Diastolic Blood Pressure

Diastolic pressure is the bottom number in a blood pressure reading. It measures the pressure in your arteries when your heart is resting between beats. It's the lower of the two numbers.

For example, in a reading like 120/80 mmHg:

  • 120 is the systolic pressure (pressure during heart beats).
  • 80 is the diastolic pressure.

What's a Normal Diastolic Pressure?

  • Normal: less than 80 mmHg
  • Elevated: Less than 80 mmHg
  • High (Hypertension Stage 1): 80–89 mmHg
  • High (Stage 2): 90 mmHg or more
  • Hypertensive crisis: Over 120 mmHg (medical emergency)

Why Diastolic Pressure Matters

Diastolic blood pressure is crucial because it shows how much pressure your arteries are under when your heart is resting. High diastolic pressure:

  • Indicates how hard your heart must work between beats
  • Can signal increased risk of heart disease
  • May indicate problems with arterial flexibility
  • Can affect blood flow to vital organs

How is Diastolic Pressure Measured?

Measuring diastolic pressure is part of the standard blood pressure measurement process.

When the blood pressure cuff deflates during measurement, the diastolic pressure is recorded at the point when the sound of blood flowing through the artery disappears completely. This represents the pressure in your arteries between heartbeats. Modern digital monitors automatically detect and display this measurement, making it easier to monitor at home.

Factors That Affect Diastolic Blood Pressure

Age

Unlike systolic pressure, diastolic typically rises until about age 50, then tends to fall gradually.

Diet

High sodium intake and poor diet can significantly impact diastolic pressure.

Physical Activity

Regular exercise helps maintain healthy diastolic pressure through improved cardiovascular fitness.

Stress

Chronic stress can lead to elevated diastolic pressure.

Medications

Various medications can affect diastolic pressure, including blood pressure medications.

How to Lower High Diastolic Pressure

Several lifestyle changes can help lower diastolic pressure:

  • Maintain a healthy weight
  • Follow a low-sodium diet
  • Exercise regularly
  • Manage stress effectively
  • Limit alcohol consumption

When to See a Doctor

Seek immediate medical attention if:

  • Your diastolic pressure exceeds 120 mmHg
  • You experience severe headaches or vision changes
  • Your readings are consistently above 80 mmHg

What if My Diastolic Pressure is Too Low?

Low diastolic pressure (below 60 mmHg) can be problematic. Symptoms may include:

  • Dizziness
  • Weakness
  • Fatigue
  • Poor concentration
  • Risk of heart tissue damage

Frequently Asked Questions About Diastolic Blood Pressure

Why might diastolic pressure be high when systolic is normal?

This condition is called isolated diastolic hypertension (IDH). It's more common in younger adults and can be related to obesity, stress, or other cardiovascular risk factors.

How does diastolic pressure change with age?

Diastolic pressure typically peaks around age 50 and then gradually decreases. This pattern differs from systolic pressure, which tends to rise steadily with age.

Is low diastolic pressure dangerous?

Very low diastolic pressure can be concerning because it might reduce blood flow to the heart. This is especially important for people with coronary artery disease.

How accurate are home readings?

Home monitors can provide reliable readings when used correctly. Ensure proper cuff fit and positioning, and follow a consistent measurement routine.