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Hypotension (Low Blood Pressure)

Low blood pressure (hypotension) can be defined as pressure so low that it causes symptoms due to diminished blood flow through the arteries and veins. 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 routinely may have blood pressures of 90/50 with no symptoms and therefore do not have low blood pressure. However, others who normally have higher blood pressures may develop symptoms of low blood pressure if their blood pressure drops to 100/60.

What is low blood pressure?
Blood pressure is the force exerted by blood on the walls of blood vessels. It constitutes one of the critically important signs of life or vital signs which include heart beat, breathing, and temperature. Blood pressure is generated by the heart pumping blood into the arteries modified by the response of the arteries to the flow of blood.
Blood pressure is expressed as systolic/diastolic, viz. 120/80.The systolic (the top number) represents the pressure in the arteries as the muscle of the heart contracts and pumps blood into them. The diastolic (the bottom number) represents the pressure in the arteries as the muscle of the heart relaxes following its contraction. Blood pressure always is higher when the heart is pumping (squeezing) than when it is relaxing.
The range of systolic blood pressure for most healthy adults falls between 90 and 120 millimeters of mercury (mm Hg). Normal diastolic blood pressure ranges between 60 and 80 mm Hg. Current guidelines define normal blood pressure range as lower than 120/80. Blood pressures over 130/80 are considered high.

Low blood pressure
Low blood pressure (hypotension) can be defined as pressure so low that it causes symptoms due to diminished blood flow through the arteries and veins. 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 routinely may have blood pressures of 90/50 with no symptoms and therefore do not have low blood pressure. However, others who normally have higher blood pressures may develop symptoms of low blood pressure if their blood pressure drops to 100/60.
While it is true that for some people who exercise and are in optimum physical condition, low blood pressure is a sign of good health and fitness. But not always.

For many people, low blood pressure can cause dizziness and fainting or indicate serious heart, endocrine or neurological disorders. Severely low blood pressure can deprive the brain, heart and other vital organs of oxygen and nutrients, leading to a life threatening condition called as hypotensive shock.
People with lower blood pressures are at a lower risk of stroke, kidney disease, and heart disease. Athletes, people who exercise regularly, people who maintain ideal body weight, and non-smokers tend to have lower blood pressures. It is therefore, desirable as long as it is not low enough to cause symptoms and damage to the organs in the body. Suddenly going from a sitting or lying position to a standing position often brings out symptoms of low blood pressure. This occurs because standing causes blood to “settle” in the veins of the lower body, and this can lower the blood pressure. If the blood pressure is already low, standing can make it worse. The development of light-headedness, dizziness or fainting caused by standing is called orthostatic hypo-tension.

When there is insufficient blood pressure to deliver blood to the coronary arteries (the arteries that supply blood to the heart’s muscle), a person may develop chest pain (angina) which may lead to even a heart attack.
When insufficient blood is delivered to the kidneys, the kidneys fail to eliminate wastes from the body, for example, urea and creatinine, adversely affecting the organ.
Shock is a life-threatening condition where persistently low blood pressure causes organs such as kidney(s), liver, heart, lung, and brain to fail rapidly.

If your heart beats 70 times per minute then by the time you are 70 years old, your heart beat count would be two and a half billion. It will pump around 48 million gallons of blood... phew! No wonder it is the most efficient organ in the body.