Blood pressure

Blood pressure is one of the vital signs, along with respiratory rate, heart rate, oxygen saturation, and body temperature.

There are four primary vital signs: body temperature, blood pressure, pulse (heart rate), and breathing rate (respiratory rate), often notated as BT, BP, HR, and RR.

Traditionally, blood pressure was measured non-invasively using auscultation with a mercury-tube sphygmomanometer.

A sphygmomanometer, also known as a blood pressure meter, blood pressure monitor, or blood pressure gauge, is a device used to measure blood pressure, composed of an inflatable cuff to collapse and then release the artery under the cuff in a controlled manner, and a mercury or mechanical manometer to measure the pressure.

Most of this pressure is due to work done by the heart by pumping blood through the circulatory system. Used without further specification, "blood pressure" usually refers to the pressure in large arteries of the systemic circulation.

This elasticity helps to maintain the blood pressure throughout the body.

Blood pressure that is too low is called hypotension, and pressure that is consistently high is hypertension.

Hypotension is low blood pressure, especially in the arteries of the left sided systemic circulation.

Blood pressure (BP) is the pressure of circulating blood on the walls of blood vessels.

Blood pressure is measured in millimetres of mercury in most of the world, and lung pressures in centimetres of water are still common.

Blood pressure also changes in response to temperature, noise, emotional stress, consumption of food or liquid, dietary factors, physical activity, changes in posture, such as standing-up, drugs, and disease.

Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure falls when standing or sitting.

Used without further specification, "blood pressure" usually refers to the pressure in large arteries of the systemic circulation.

Arteries have a blood pressure higher than other parts of the circulatory system.

In the short term, blood pressure is regulated by baroreceptors which act via the brain to influence the nervous and the endocrine systems.

They sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained.

Blood pressure is usually expressed in terms of the systolic pressure (maximum during one heartbeat) over diastolic pressure (minimum in between two heartbeats) and is measured in millimeters of mercury (mmHg), above the surrounding atmospheric pressure. MAP is the average of blood pressure over a cardiac cycle and is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP)):

Throughout the cardiac cycle, blood pressure increases and decreases.

MAP is the average of blood pressure over a cardiac cycle and is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP)):

Central venous pressure (CVP) is the blood pressure in the venae cavae, near the right atrium of the heart.

In the short term, blood pressure is regulated by baroreceptors which act via the brain to influence the nervous and the endocrine systems.

For instance, the arterial blood pressure in mammals is homeostatically controlled, and measured by stretch receptors in the walls of the aortic arch and carotid sinuses at beginnings of the internal carotid arteries.

However, semi-automated methods have become common, largely due to concerns about potential mercury toxicity, although cost, ease of use and applicability to ambulatory blood pressure or home blood pressure measurements have also influenced this trend.

Ambulatory blood pressure monitoring (ABPM) measures blood pressure at regular intervals.

If systolic blood pressure is elevated (>140 mmHg) with a normal diastolic blood pressure (

In medicine, systolic hypertension is defined as an elevated systolic blood pressure (SBP).

Blood pressure that is too low is called hypotension, and pressure that is consistently high is hypertension. Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysms, and is the leading cause of chronic kidney failure.

Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated.

Sometimes it can be an acute problem, for example hypertensive emergency.

Hypertensive urgency is defined as having a systolic blood pressure over 180 mmHg or a diastolic blood pressure over 110 mmHg.

However, occasionally there is a consistent difference greater than 10 mmHg which may need further investigation, e.g. for peripheral arterial disease or obstructive arterial disease.

PAD is typically diagnosed by finding an ankle-brachial index (ABI) less than 0.90, which is the systolic blood pressure at the ankle divided by the systolic blood pressure of the arm.

Blood pressure also changes in response to temperature, noise, emotional stress, consumption of food or liquid, dietary factors, physical activity, changes in posture, such as standing-up, drugs, and disease.

Portal venous pressure is the blood pressure in the hepatic portal vein, and is normally between 5-10 mmHg.

However, occasionally there is a consistent difference greater than 10 mmHg which may need further investigation, e.g. for peripheral arterial disease or obstructive arterial disease. Long-term hypertension is a risk factor for many diseases, including heart disease, stroke and kidney failure.

There is also evidence that a Mediterranean diet may be more effective than a low-fat diet in bringing about long-term changes to cardiovascular risk factors (e.g., lower cholesterol level and blood pressure).

Blood pressure is usually expressed in terms of the systolic pressure (maximum during one heartbeat) over diastolic pressure (minimum in between two heartbeats) and is measured in millimeters of mercury (mmHg), above the surrounding atmospheric pressure.

In the past, most attention was paid to diastolic pressure; but nowadays it is recognized that both high systolic pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk factors.

Pulse pressure is the difference between systolic and diastolic blood pressure.

For those with heart valve regurgitation, a change in its severity may be associated with a change in diastolic pressure.

A heart valve opens or closes incumbent on differential blood pressure on each side.

However, measurement of pressures in the venous system and the pulmonary vessels plays an important role in intensive care medicine but requires invasive measurement of pressure using a catheter.

Reflex syncope is a brief loss of consciousness due to a neurologically induced drop in blood pressure.

Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysms, and is the leading cause of chronic kidney failure.

Other less common symptoms include weakness, light-headedness, palpitations, and abnormalities in heart rate or blood pressure.