What is low diastolic blood pressure?
Blood pressure readings use two numbers recorded in millimeters of mercury (mm Hg). The two numbers measure:
Systolic blood pressure: This is the top number, and is the higher of the two. It measures how much pressure the blood applies to the artery walls when the heart beats.
Diastolic blood pressure: This is the lower number, which shows the pressure that the blood applies to the artery walls when the heart rests between beats.
A blood pressure reading will show the systolic blood pressure number first, and diastolic blood pressure second. A doctor will assess a person’s blood pressure by considering both numbers. In most adults, a healthy reading is usually less than 120/80 mm Hg. Low blood pressure, or hypotension, is blood pressure that is below 90/60 mm Hg.
Low diastolic blood pressure, or isolated diastolic blood pressure, is when the diastolic blood pressure falls below 60 mm Hg, while the systolic blood pressure remains at a normal level.
When the heart rests in between beats, the coronary arteries receive and supply the heart with oxygen-rich blood. If the diastolic pressure is too low, the heart will not get the amount of blood and oxygen it needs. This may cause the heart to weaken over time.