High Blood Pressure

Frequently Asked Questions

5. Blood pressure is always given as two numbers. What do they mean?

Blood pressure is always given as two numbers, the systolic and diastolic pressures. Your systolic pressure is the pressure of blood in the vessels when your heart beats. Your diastolic pressure is the pressure between beats when your heart relaxes. Although both numbers are important, having only high systolic blood pressure, a condition called isolated systolic hypertension, is more common in older adults, and can cause as much harm as high blood pressure in which both numbers are too high.

The measurements are written one above or before the other -- for example, 120/80 mmHg. The top, or first, number is the systolic and the bottom, or second number, is the diastolic. If your blood pressure is 120/80, you say that it is "120 over 80."