What is diastolic blood pressure?

According to the American Heart Association, diastolic blood pressure refers to the amount of pressure against artery walls between heartbeats or when the heart is at rest. The second number in a blood pressure reading, diastolic pressure is considered normal when it is less than 80.

According to WebMD, a diastolic reading that falls between 80 and 89 indicates prehypertension, while a reading of 90 or higher is indicative of high blood pressure. The American Heart Association warns that any diastolic reading over 110 is considered a hypertensive crisis and requires immediate medical attention. The organization also recommends living a healthy lifestyle to reduce and/or prevent high blood pressure.