Blood pressure

Blood pressure
A healthcare worker measuring blood pressure using sphygmomanometer.
MeSH	D001795
MedlinePlus	007490
LOINC	35094-2

Blood pressure is a measurement used in medicine. In the body, the arteries carry blood away from the heart. As blood travels through the arteries, it presses against the walls of the arteries. Blood pressure measures how hard the blood is pushing against the walls of the arteries.

Usually, "blood pressure" measures the pressure in larger arteries delivering blood to body parts other than the lungs, like the brachial artery in the arm. Blood pressure is usually measured in millimeters of mercury (mmHg).

There are two numbers in a blood pressure. The first is the systolic pressure. It measures how hard the blood pushes against the walls of the arteries when the heart is in systole (beating and pushing out blood). This is when the pressure against the walls of the arteries is highest. The second number is the diastolic blood pressure. It measures how hard the blood pushes against the walls of the arteries when the heart is in diastole (resting between beats and not pushing out any blood). For example, in the picture on this page, the pressure on the walls of the arteries is 122 mmHg when the heart is beating, and 65 mmHg when the heart is resting. This blood pressure would be written as "122/65" and read as "122 over 65."

Mean arterial pressure is a person's average blood pressure. Pulse pressure is the difference between the systolic and diastolic pressures.

To measure blood pressure, doctors use a device called a sphygmomanometer.

Normal Blood Pressure

A digital blood pressure meter showing a blood pressure of 122 systolic and 65 diastolic, read as "122 over 65" or 122/65 mmHg.

Blood pressure is usually lower for children and gets higher as a person gets older.

For healthy adult humans, the systolic blood pressure should be below 120, and the diastolic blood pressure should be below 80. However, blood pressure can be very different for each person. Blood pressure also changes naturally during the day (in a circadian rhythm). It gets lower during sleep and gets higher when a person gets up. It is lower when a person is resting and higher during activity. Many other things - like stress, disease, drugs, and what a person eats - can change blood pressure. Even the stress of having blood pressure taken can make it higher. This is called "white coat hypertension." Blood pressure is a key component of a person's overall health. Both high and low blood pressure can pose significant health risks.

High Blood Pressure

Main article: Hypertension

Hypertension, or high blood pressure, is a condition where the force of the blood against the walls of the arteries is consistently too high. Hypertension is a common condition and affects about one in every three adults in the United States. It is often referred to as the "silent killer" because it frequently presents no symptoms until it has caused significant damage to the heart and arteries.

Uncontrolled high blood pressure can lead to serious complications, including heart attack, stroke, and kidney disease. Regular monitoring and appropriate treatment can help control blood pressure and reduce the risk of these complications.

Low Blood Pressure

Main article: Hypotension

Hypotension, or low blood pressure, occurs when blood pressure is consistently lower than normal. This can lead to insufficient blood flow to the heart, brain, and other vital organs. Symptoms of hypotension may include dizziness, fainting, and in severe cases, shock.

While low blood pressure might seem desirable, especially in light of the risks associated with high blood pressure, it can be dangerous if it drops too low. Extremely low blood pressure can deprive the body's organs of the oxygen and nutrients they need to function properly.

Related pages

• Blood pressure
• Cardiovascular disease
• Heart disease

References

Blood pressure Resources
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