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Blood pressure is considered a "vital sign" and measures the force of the blood on the walls of blood vessels as it travels through the body. It is a key indicator of heart health. The measurement consists of two numbers, and it's important that both are within a normal range. The first is the systolic number, and measures the pressure during a heartbeat. The lower, second number is diastolic and measures the force between heartbeats. If either of these blood pressure numbers appear abnormally high, it indicates a potentially dangerous condition called high blood pressure (HBP), also known as hypertension.
Blood pressure reading is a standard part of most medical examinations. It records the outward pressure or force placed on the walls of the blood vessels, like arteries, as the blood circulates through the body. The force is generated by the heart as it pumps the blood and can be affected by friction and resistance from blood vessel walls. This measurement helps medical professionals determine how hard a person's heart is working; blood pressure numbers should fall within a normal range in a healthy individual.
Blood pressure is reported using two numbers, and many people don't completely understand what these numbers mean. The standard unit of measurement for the blood pressure numbers is millimeters of mercury, abbreviated as mmHg. The higher number that comes first is called systolic pressure. This is the pressure on the artery walls during a heartbeat while the heart muscle is working. The second number is the diastolic pressure, representing the outward force on the artery walls while the heart is at rest between heartbeats.
The normal systolic range is typically between 100 and 120 mmHg. The diastolic number should be between 60 and 80 mmHg to be considered normal. A reading of 110 systolic and 70 diastolic is usually spoken as "110 over 70" and is written as a fraction "110/70 mmHg." When the blood pressure numbers fall within the normal range, it's a positive indicator of health; lower numbers aren't usually considered to be a cause for concern.
Blood pressure numbers above the normal range may indicate a problem. If the systolic number is between 120 and 139 mmHg and the diastolic pressure is 80 to 89 mmHg, the person has a condition called prehypertension which should be carefully monitored. Numbers above systolic 140 mmHg and diastolic 90 mmHg indicate high blood pressure which requires treatment including lifestyle changes and medication. High blood pressure can be very dangerous, possibly leading to severe medical issues including stroke and heart attack. A blood pressure reading above 180/110 mmHg is called hypertensive crisis and requires emergency medical attention.