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Low Blood Pressure Causes

What is Low Blood Pressure?

You may wonder what is considered low blood pressure? Low blood pressure is the opposite of hypertension or high blood pressure.

An individual’s blood pressure is measured and expressed in two numbers, specifically as systolic/diastolic blood pressure (e.g. 120/80 mmHg). The first is called the systolic pressure which represents the pressure in the arteries as the muscle of the heart contracts and pumps blood into the arteries. The second is called the diastolic blood pressure which occurs when your heart relaxes and represents the pressure measurement in the arteries as the muscle of the heart relaxes after it contracts. When the heart muscle is pumping (squeezing), blood pressure is always higher than when it is relaxing, thus the systolic pressure or top blood pressure measurement is the higher of the two numbers. The higher the systolic or diastolic pressure, and the longer it stays high, the more damage this causes to the blood vessels.

A blood pressure of 90/120 millimeters of mercury (mm Hg) is considered to be the normal systolic blood pressure for most healthy adults falls. Normal diastolic blood pressure ranges between 60 and 80 mm Hg. Normal blood pressure is currently defined by guidelines as lower than 120/80.

There are many who are looking for specific low blood pressure numbers or measurement. However, what is considered low blood pressure is marked primarily by signs and symptoms of low blood flow and not by a specific blood pressure number, unlike high blood pressure (e.g. over 139/89). Those who seem to have low blood pressure numbers but exhibit no symptoms of low blood pressure, may not actually have low blood pressure. While those who normally have high blood pressure may develop symptoms of low blood pressure if their blood pressure drops 30 mmHg or more from their usual or baseline blood pressure.
Low blood pressure or hypotension is pressure so low that symptoms and signs occur because of the low flow of blood through the arteries and veins. When the flow of blood is severely low, the supply of oxygen and nutrients to the vital organs such as the brain, heart, and kidney may be insufficient to support normal functioning and can result to fainting, loss of consciousness or in extreme cases, shock which is a severe form of hypotension and a life-threatening condition that must be treated immediately.

What causes low blood pressure?

The most common reason for hypotension is reduced blood volume called hypovolemia. Heart disease due to weakened heart muscle which cause the heart to weaken and lessen the amount of blood it pumps brings about low blood pressure condition. Other causes of low blood pressure include hemorrhage or severe internal bleeding, insufficient fluid intake as in starvation, dehydration resulting from diarrhea and vomiting and nutritional deficiencies.

Other triggers include some medications such as diuretics, heart medications and antidepressants that can produce hypovolemia as a side effect. Medications used in treating high blood pressure can excessively slow the rate at which the heart pumps blood and can result in symptomatic low blood pressure especially among the elderly who are extremely sensitive to these medications. Narcotic drugs and alcohol can also cause low blood pressure.

How do you know if you have low Blood Pressure?

Sometimes even healthy individuals may experience weakness, dizziness, and fainting which are common low blood pressure signs. While this can lead one to suspect that such symptoms are low blood pressure signs, it is important to identify the cause since a wide range of underlying conditions may cause these symptoms. Your doctor can advise if you are having significant low blood pressure and help in identifying the cause for the low blood pressure condition so that appropriate treatment can be applied.