We all know that blood pressure is expressed with one number over another: 120/80. Fewer among us remember that the top number is called the systolic and the bottom number is called the diastolic. Or if we do remember, we get them mixed up. But there’s a simple mnemonic device to keep the two numbers straight: the lower, bottom number, which represents the blood pressure in the lower chamber of the heart, begins with D – as in “down”. The upper number, which represents the pressure in higher chambers of the heart, begins with S – as in “sky”.
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Learn more about blood pressure.