Importance of the Diastolic Blood Pressure Reading

In a blood pressure reading, the diastolic reading is the lower (bottom) number. It represents a time when the heart is at rest and refilling after creating pressure within the veins from pumping out blood (systolic number). It is important to understand blood pressure readings in order to avoid the often serious health problems that can result from high blood pressure.

Interpreting the Numbers

• A diastolic reading of 80 mmHg (millimeters of mercury) or lower is considered normal. Prehypertension is indicated with a diastolic reading of 80 to 89 mmHg, while hypertension (high blood pressure) is indicated by a diastolic reading of 90 mmHg or above.

High Blood Pressure

• It is important to get your blood pressure checked yearly or more often if high blood pressure has been detected. High blood pressure greatly increases the risk of heart attack and stroke, so it is important to maintain a healthy blood pressure reading.

Kidney Disease

• A high diastolic reading can also be a sign of kidney disease. Normally, the kidneys excrete more sodium chloride (salt) as larger amounts are absorbed into the body. When the kidneys cannot keep the amount of minerals in the body balanced, there's higher pressure in the arteries due to decreased blood flow.

Low Diastolic Reading

• A severely low reading, or sudden lowering, of the diastolic number can be an indication that the body may not be getting a proper amount of nutrients and oxygen. Low blood pressure could be a sign of heart disease, blood loss, infection, pregnancy and dehydration.

Diastolic Dysfunction

• In some people, the heart contracts normally but does not rest normally. This leads to diastolic dysfunction in which the lower chambers of the heart (the ventricles) do not relax and cause an increase in pressure and an overflow of blood going to the lungs.

Prevention/Solution

• To lower blood pressure readings, physicians may ask patients to lose weight; reduce their intake of saturated fats, cholesterol and salt; and decrease alcohol consumption.