Blood pressure readings consist of two numbers. While most people concentrate more on the bigger one, a thorough examination of diastolic should be done. Therefore, what is meant by diastolic blood pressure?
Diastolic blood pressure indicates how much pressure the blood is exerting against the artery walls when the heart is relaxed between beats. Diastolic blood pressure is the bottom number of the blood pressure reading.
We’ll take an in-depth look into diastolic blood pressure. In addition, if you’re wondering what is considered high or low diastolic pressure, keep reading.
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Diastolic Blood Pressure
While the heart beats it pumps blood through the circulatory system. When this happens, the blood puts pressure against the walls of the arteries. In addition, when the heart relaxes between beats, there is pressure against the artery walls.
The pressure while the heart relaxes is called diastolic blood pressure 1.
The blood pressure reading has two numbers, a top number and a bottom number. Which blood pressure number is diastolic? Diastolic is the bottom number of the blood pressure reading.
Therefore, in the following examples of blood pressure readings, the diastolic number is indicated:
- 120/80 – 80 is diastolic
- 160/90 -90 is diastolic
- 80/50 – 50 is diastolic
When the heart is beating, pumping blood, the pressure against the artery walls is called systolic blood pressure. I wrote a blog post on systolic blood pressure which you can check out here, systolic blood pressure.
Diastolic Blood Pressure Ranges
There are five blood pressure ranges:
- High Blood Pressure Stage 1
- High Blood Pressure Stage 2
- Hypertensive Crisis
Normal Diastolic Blood Pressure
What is the normal range of diastolic pressure for adults? A normal range of diastolic blood pressure for adults is 60 mmHg to 79 mmHg.
If diastolic is less than 80 mmHg and systolic is less than 120 mmHg, a doctor will typically suggest the following:
- Follow a heart healthy diet.
- Engage in regular physical activity.
- Continue avoiding unhealthy habits like excess alcohol or smoking.
- Monitor blood pressure readings.
- Attend regular physicals.
Elevated Blood Pressure
What is the elevated diastolic blood pressure range? The elevated range is when diastolic blood pressure is less than 80 mmHg and systolic blood pressure is between 120-129 mmHg.
Blood pressure in this range is elevated because of systolic pressure and not the less than 80 diastolic. If blood pressure is elevated, the risk of developing high BP is greater. For consistent readings in this range, a doctor will typically recommend the following:
- Recommend lifestyle changes.
- Improve the nutrition plan.
- Regular physical activity.
- Avoid excess alcohol.
- Stop smoking.
- No illegal drugs.
- Stress management.
- Monitor blood pressure readings.
- Attend scheduled physician visits.
High Diastolic Blood Pressure
High diastolic blood pressure is broken down into two high blood pressure categories:
- High Blood Pressure Stage 1: High diastolic blood pressure is between 80-89 mmHg.
- High Blood Pressure Stage 2: High diastolic blood pressure is 90 mmHg or higher.
For high blood pressure stage 1, doctors will recommend lifestyle changes and may consider prescribing medicine based on the risk of cardiovascular disease 2.
For high blood pressure stage 2, doctors are likely to recommend lifestyle changes and medication.
Diastolic is one of over ten topics discussed in my BP Chart article. Learn more about BP categories and download my free BP Category Chart for easy reference. Check out the article here, What Is The Blood Pressure Chart? All Five Categories.
Diastolic Hypertensive Crisis
What is sudden high diastolic blood pressure? Sudden high diastolic blood pressure is higher than 120 mmHg. Diastolic blood pressure over 120 mmHg is in the hypertensive crisis range and requires medical assistance.
If you take your blood pressure and either number is 180/120 or greater, wait about 5 minutes and take it again. If the 2nd reading is just as high and you are not experiencing any of the following symptoms, then contact your doctor and be guided by them:
- Chest pain
- Shortness of breath
- Back pain
- Change in vision
- Difficulty breathing
If your numbers indicate a hypertensive crisis and you are experiencing one of the above symptoms you must go to a hospital immediately. The consequences of a hypertensive crisis can be severe or fatal 3.
Why Diastolic Blood Pressure Is Important
Typically, for people over 50, more attention is directed to the higher number, systolic blood pressure, as a major risk factor for cardiovascular disease 4. Therefore, why is diastolic pressure important?
Diastolic pressure is important because an elevated diastolic pressure may be used to make a diagnosis of high blood pressure. In addition, elevated diastolic pressure means there is an increased risk of developing elevated systolic blood pressure as a person ages.
Recent studies have researched people ranging from 40 to 89 years of age. They found for each 10 mmHg diastolic number increase in blood pressure, the risk of death from ischemic heart disease and stroke doubles.
Ischemic heart disease is a term given to heart problems that are caused by narrowed heart arteries.
On the other hand, if diastolic blood pressure is too low, meaning coronary arteries aren’t getting enough blood pressure, the heart is going to lack oxygen and blood. This is called ischemia and may weaken the heart over time which can lead to heart failure.
The coronary arteries which surround the aortic valve in the heart only get blood when the aortic valve closes, and this happens in diastole 5.
What is diastole? Diastole is the part of the cardiac cycle when the heart is relaxed between beats and refills with blood.
Diastolic blood pressure is measured at the moment diastole is occurring 6.
Diastolic Blood Pressure in the 50s
Is 50 a normal diastolic number? A diastolic number of 50 is not normal diastolic blood pressure. It is considered low blood pressure. Any diastolic blood pressure number under 60 mmHg is considered low blood pressure.
Low diastolic blood pressure can occur with a low systolic or with a normal systolic pressure. When diastolic is low but systolic isn’t, it’s called isolated diastolic blood pressure. This can be dangerous for your heart 7.
Unlike the rest of the body, your heart receives blood during diastolic, when it’s not beating. This can lead to symptoms of a weakening heart.
The American Heart Association or the American College of Cardiology hasn’t determined a set number range for low blood pressure. Most experts consider low diastolic pressure under 60 mmHg 8.
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- American Heart Association: Diastolic blood pressure
- American Heart Association: Understanding Blood Pressure Readings
- National Center for Biotechnology Information: Hypertensive Crisis
- National Center for Biotechnology Information: High Blood Pressure and All-Cause and Cardiovascular Disease Mortalities in Community-Dwelling Older Adults
- UAB News: Diastolic blood pressure: How low is too low?
- Merriam-Webster: diastole
- National Center for Biotechnology Information: Cardiovascular risks associated with diastolic blood pressure and isolated diastolic hypertension
- Michigan Medicine: Low Blood Pressure (Hypotension)