Blood pressure (BP) refers to the force exerted by the circulating blood per unit area on the walls of the blood vessels. It is one of the main vital signs of a healthy body. It is expressed as systolic pressure over diastolic pressure, and is clinically reported in millimeters of mercury (mm Hg). It is measured by an instrument called sphygmomanometer.
Systolic blood pressure comes from the word ‘systole’, which means contraction of the heart chambers. It represents the pressure that is exerted by the blood on the arteries when the muscle of the heart contracts and blood is pumped through the blood vessels to the rest of the body. This is the maximum pressure exerted by the blood on the arteries. On the other hand, diastolic pressure is the pressure that blood exerts on the arteries, when the heart relaxes after a contraction and the chambers of the heart get filled with blood.
A systole is divided into three types:
Electrical and Mechanical: It involves the electrical activity stimulating the myocardium of the heart’s chambers. It generates an action which makes the muscles contract. Mechanical contraction follows the electrical contraction, which forces the blood through the heart.
Atrial Systole: This refers to the contraction of the myocardium of the left and right atria.
Ventricular Systole: When there is a contraction of the myocardium of the left and right ventricles, it is referred to as a ventricular systole.
Normal Range for Systolic and Diastolic Pressure
Systolic pressure is the maximum pressure in the arteries, occurring towards the end of a cardiac cycle, when the ventricles are going through a contraction. A normal, healthy adult has a systolic pressure of 90-120 mm Hg. It is not permanent and varies from one heartbeat to the other. It could get affected by drug consumption, exercise, stress, and illness. On the other hand, normal reading for diastolic pressure is 80 mm Hg.
High blood pressure can be caused by hereditary factors, obesity, kidney failure, and high salt intake. A person is diagnosed with hypertension when systolic pressure ranges from 120 to 139 mm Hg and diastolic pressure from 80 to 89 mm Hg. In case of people affected by hypertension, the reading is 140/90 mm Hg or more. In case of hypotension, the systolic pressure is less than 90 mm Hg or diastolic pressure is less than 60 mm Hg.
Isolated Systolic Hypertension (ISH):
ISH occurs when the systolic reading is higher in relation to the normal diastolic reading. In 1993, ISH was defined as systolic blood pressure of more than 140 mm Hg combined with normal diastolic pressure.
Usually, middle-aged people develop hypertension, but nowadays, it is even diagnosed in young people as well. Following a healthy diet and exercise regimen coupled with regular checkups can help keep these problems at bay.