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What is Diastolic Pressure?

Svetlana Arutyunyan
Svetlana Arutyunyan

Diastolic blood pressure measures the pressure exerted by the heart against artery walls when the heart is at rest. Usually displayed in conjunction with the systolic blood pressure, the diastolic pressure marks the end of the cardiac cycle, when the heart fills with blood. The systolic blood pressure, on the other hand, marks the beginning of the cardiac cycle, when the heart contracts. The difference between systolic and diastolic blood pressure is called pulse pressure.

One of the instruments used to read heart pressure is a sphygmomanometer. Written as a fraction, heart pressure is measured by millimeters of mercury (mmHg). Systolic blood pressure is represented by the top, larger number, while diastolic blood pressure is the lower, smaller number.

The difference between an individual's systolic and diastolic pressures is referred to as pulse pressure.
The difference between an individual's systolic and diastolic pressures is referred to as pulse pressure.

Blood pressure can change throughout the day, depending on temperature, exercise, narcotic use, and posture. It is advised that an individual checks his or her blood pressure several times during the day in order to get a more accurate assessment. One can check his or her blood pressure at a doctor’s office, or in the comfort of the home. A disadvantage of going to the doctor is that an individual may feel nervous about the visit, and thus inaccurately display a higher blood pressure. This is called white-coat hypertension.

An individual suffering from an eating disorder may experience low blood pressure.
An individual suffering from an eating disorder may experience low blood pressure.

For a healthy adult, 18 years of age and older, a normal systolic pressure is considered between 90 and 119 mmHg. A normal diastolic blood pressure is between 60 and 79 mmHg. An individual whose systolic blood pressure is below 90 and diastolic pressure below 60 may suffer from hypotension. On the other hand, a systolic pressure above 140, and a diastolic pressure above 90, indicates hypertension. One of the ways in which an individual can lower his or her blood pressure is by losing weight, eating healthier, and exercising.

High blood pressure may lead to heart attack or stroke.
High blood pressure may lead to heart attack or stroke.

High blood pressure, called hypertension, can cause kidney disease, heart failure, blindness, heart attack, and stroke. Low blood pressure, called hypotension, can cause dizziness, nausea, and fainting. Some of the causes of hypotension include dehydration, gland disorders, and infections.

For younger people, diastolic blood pressure is a good indicator of hypertension, since higher diastolic pressure increases the likelihood of suffering from hypertension. Systolic blood pressure rises as people get older, and becomes a more important factor in determining hypertension. Older people with a higher systolic blood pressure are more likely to experience a stroke, kidney disease, and heart attack.

Taking blood pressure medications before bed may cause better blood pressure control overall.
Taking blood pressure medications before bed may cause better blood pressure control overall.

Adults over the age of 18 are advised to check blood pressure once a year. An individual may not experience any symptoms of high blood pressure, which is why conducting the check is imperative. Checking blood pressure for individuals who are taking medication for high blood pressure may reveal whether their treatment is working.

Discussion Comments

gremlins

I have heard that some people have a naturally higher or lower blood pressure, for instance, someone's normal blood pressure would be considered "high" by regular standards. Is this true, and if so, what causes it? Is this related to diastolic pressure?

PandaGolden

Thanks for this article -- I kept hearing the term thrown around on medical TV shows in connection to high blood pressure, but I never quite knew how they measured things like that. Now the next time I got to the doctor at least I'll know what's going on when they strap that cuff on!

anon106714

why is the normal rate of diastolic pressure is given more importance while checking BP?

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    • The difference between an individual's systolic and diastolic pressures is referred to as pulse pressure.
      By: Monkey Business
      The difference between an individual's systolic and diastolic pressures is referred to as pulse pressure.
    • An individual suffering from an eating disorder may experience low blood pressure.
      By: Sylvie Bouchard
      An individual suffering from an eating disorder may experience low blood pressure.
    • High blood pressure may lead to heart attack or stroke.
      By: Barabas Attila
      High blood pressure may lead to heart attack or stroke.
    • Taking blood pressure medications before bed may cause better blood pressure control overall.
      By: Gabriel Blaj
      Taking blood pressure medications before bed may cause better blood pressure control overall.
    • Individuals who are overweight have a greater risk of developing high blood pressure.
      By: konami11
      Individuals who are overweight have a greater risk of developing high blood pressure.
    • Systolic blood pressure is the top number when reading blood pressure levels, and the bottom number is diastolic pressure.
      By: dambuster
      Systolic blood pressure is the top number when reading blood pressure levels, and the bottom number is diastolic pressure.