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February 10, 2010
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Low Blood Pressure
(Hypotension)

Medical Authors: John P. Cunha, DO and Dennis Lee, MD
Medical Editor: Jay W. Marks, MD

Doctor to Patient

Low Blood Pressure and Stress

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Learn about low blood pressure and stress.

Viewer Question: I've heard that stress may cause high blood pressure, but can it also cause low blood pressure?

Doctor's Answer: Low blood pressure is hard to define, because a lowered blood pressure can occur naturally in persons who exercise regularly, keep a normal weight, and eat a healthy diet. Many experts use the arbitrary criteria of a systolic (top) pressure of 90 or lower or a diastolic (bottom) pressure of 60 or less to be the cutoff levels used to define low blood pressure. But in some cases, low blood pressure accompanies certain medical conditions and may be a sign of life-threatening illness.

Read more about stress and low blood pressure »


Top Searched Low Blood Pressure Terms:

orthostatic hypotension, diastolic, systolic, causes, treatment, symptoms, dizziness

What is low blood pressure?

Blood pressure is the force exerted by circulating blood on the walls of blood vessels, and constitutes one of the principal vital signs of life, which also include heart beat, rate of breathing, and temperature. Blood pressure is generated by the heart pumping blood into the arteries and is regulated by the response by the arteries to the flow of blood.

An individual's blood pressure is expressed as systolic/diastolic blood pressure, for example, 120/80.The systolic blood pressure (the top number) represents the pressure in the arteries as the muscle of the heart contracts and pumps blood into them. The diastolic blood pressure (the bottom number) represents the pressure in the arteries as the muscle of the heart relaxes after it contracts. Blood pressure always is higher when the heart is pumping (squeezing) than when it is relaxing.

Systolic blood pressure for most healthy adults falls between 90 and 120 millimeters of mercury (mm Hg). Normal diastolic blood pressure falls between 60 and 80 mm Hg. Current guidelines define normal blood pressure as lower than 120/80. Blood pressures over 130/80 are considered high. High blood pressure increases the risk of developing:

Low blood pressure (hypotension) is pressure so low it causes symptoms or signs due to the low flow of blood through the arteries and veins. When the flow of blood is too low to deliver enough oxygen and nutrients to vital organs such as the brain, heart, and kidney, the organs do not function normally and may be permanently damaged.

Unlike high blood pressure, low blood pressure is defined primarily by signs and symptoms of low blood flow and not by a specific blood pressure number. Some individuals may have a blood pressure of 90/50 with no symptoms of low blood pressure and therefore do not have low blood pressure. However, others who normally have high blood pressure may develop symptoms of low blood pressure if their blood pressure drops to 100/60.



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Low Blood Pressure - Causes

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Low Blood Pressure

What are the kidneys?

The kidneys play key roles in body function, not only by filtering the blood and getting rid of waste products, but also by balancing levels of electrolytes in the body, controlling blood pressure, and stimulating the production of red blood cells.

The kidneys are located in the abdomen toward the back, normally one of each side of the spine. They get their blood supply through the renal arteries directly from the aorta and send blood back to the heart via the renal veins to the vena cava. (The term "renal" is derived from the Latin name for kidney.)

The kidneys have the ability to monitor the amount of body fluid, the concentrations of electrolytes like sodium and potassium, and the acid-base balance of the body. They filter waste products of body metabolism, like urea from protein metabolism and uric acid from DNA breakdown. Two waste products in the blood can be measured: blood urea nitrogen (BUN) and ...

Read the Kidney Failure article »











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