Blood pressure measurement historyBefore the first sphygmomanometer, doctors put tubes in arteries to measure systolic blood pressure. Happily, in 1881 Samuel Siegfried Karl Ritter von Basch figured out a way to measure blood pressure in a less invasive way, using a rubber ball that restricted blood flow to the artery and attaching that to a column of mercury.
How the sphygmomanometer worksWhat is happening when the cuff is put on your arm? What is the doctor, or nurse, or machine, trying to detect? When the cuff is pumped up, it feels like they are cutting off blood flow to your hand. Guess what? That is what the cuff is supposed to do. When the healthcare provider can hear the blood flowing again, the gauge shows the systolic pressure. When there is no sound from the artery, the number on the gauge is the diastolic pressure. The sounds from the artery were figured out by a Russian physican, N.S. Korotkoff, in 1905. Because of this achievement they are named after him (Korotkoff sounds).
What your blood pressure numbers mean
Blood pressure is composed of a ratio of two numbers. The higher of the numbers that is the one on top is called systolic. Systolic pressure measures the pressure in the arteries when the heart contracts. Having systolic pressure below 120 mmHg is ideal. Prehypertension is indicated when systolic pressure is between 120 and 139 mmHg. Stage 1 Hypertension occurs when systolic pressure is between 140 and 159 mmHg. Hypertension Stage 2 is when systolic pressure is 160 mmHg or higher. If your pressure is over 180 mmHg, it is an emergency and care is needed immediately.(<=Click to Tweet About This)The bottom and smaller number in the ratio is diastolic. Diastolic pressure is measuring the pressure in your arteries when your heart is resting between heartbeats. This is the time when the heart refills with blood. If your diastolic pressure is below 80 mmHg, you are in great shape. Prehypertension occurs when diastolic pressure is between 80 and 89 mmHg. If the diastolic pressure is 90 to 99, you are in Stage 1 Hypertension. Stage 2 Hypertension occurs from 100 mmHg and up. A dangerous and emergency situation has developed if your diastolic goes over 110 mmHg.(<=Click to Tweet About This) Looking at the difference in the systolic and diastolic pressure gives another measure called pulse pressure. For example, if your blood pressure is 140 mmHg /80 mmHg, you pulse pressure is 140 minus 80 or 60. Pulse pressure should be between 30 and 60 mmHg.