Low Blood Pressure or hypotension, as it is known in medical parlance, refers to the fall in blood pressure below the normal.
It is a condition in which the action of the heart in forcing the blood through the arteries is weak. This is a direct outcome of a weakened and devitalised condition of the system.
The blood pressure is measured with an instrument called Sphygmomanometer in millimeters of mercury. The highest pressure reached during each heart beat is called systolic pressure and the lowest between two beats is known as diastolic pressure.
The normal systolic pressure ranges between 100-140 and diastolic pressure ranges between 60-90. This varies from person to person, according to the age, sex and emotional status. A person is said to suffer from low blood pressure if there is difference of 40 mm or more between the present blood pressure and his usual blood pressure. Thus for instance, if the usual reading is 160/90 and it comes down to 120/70 or less, it can be taken as low blood pressure.
Symptoms
The patient with chronic low blood pressure may complain of lethargy, weakness, fatigue and dizziness. He may faint, especially if arterial pressure is lowered further when he assumes an erect position. Other symptoms of low blood pressure are darkness before the eyes and cold sweating. These symptoms are presumably due to a decrease in prefusion of the brain, heart, skeleton muscle and other organs.
Causes
The most important cause of low blood pressure is faulty nutrition. It makes the tissues forming the walls of blood vessels to become overrelaxed and oxygen and nutrients to the tissues. Malnutrition can result from diet deficient in calories, proteins, vitamin C or almost any one of the B Vitamins.
Sometimes, the blood pressure falls rapidly because of haemmorrhage or loss of blood. Low blood pressure may also develop gradually because of slow bleeding in the gastrointestinal tract, or through the kidneys or bladder. Emotional problems are a far more frequent cause of low blood pressure. To a lesser degree, prolonged disappointment and frustration may result in a subnormal blood pressure.
Sometimes in young women with no abnormal disease, blood pressure tends to be on the low side, say, 90/60 or less. Heredity also plays a role and low blood pressure runs in certain families. Their blood pressure continues to be low, irrespective of what they eat and how they live.