​An ideal blood pressure is 120/80 which is spelt as 120 over 80. In a blood pressure reading, 120 is systolic and 80 is diastolic. Diastolic blood pressure (DBP) is a critical component of blood pressure readings, representing the pressure in the arteries when the heart is at rest between beats. While systolic blood pressure (SBP) measures the force when the heart contracts and pumps blood into the arteries, diastolic pressure reflects the arterial pressure during the heart's relaxation phase. Here are several reasons why diastolic blood pressure matters and why you should not ignore an elevated diastolic reading:​