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: systolic and diastolic pressures.

  • Systolic pressure is the pressure of blood in the vessels when your heart beats.
  • Diastolic pressure is the pressure between beats when your heart relaxes.

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."