It is important to have your blood pressure measured regularly and know your blood pressure numbers. Both numbers are important. We measure blood pressure with two numbers. The top number is the systolic blood pressure and is the largest number. This is the pressure in your blood vessels when your heart beats and pumps blood. The bottom number is the diastolic blood pressure. This is the pressure in your blood vessels when your heart relaxes and fills with blood.

The higher your systolic or diastolic pressure is, and the longer these numbers are high, the more damage occurs to your blood vessels. Strokes and heart attacks are caused by damaged blood vessels.
Regular blood pressure monitoring is especially important if your blood pressure is between 130/85 and 139/89. This is called “high normal” blood pressure. More than half of people with “high normal” blood pressure develop hypertension within four years unless they make lifestyle changes.
You can help your doctor to diagnose hypertension by measuring your blood pressure at home. Home blood pressure monitoring at home may also be important if you have kidney disease or diabetes.
If you are measuring your blood pressure at home:
View Approved Home Blood Pressure Devices
Blood pressure monitors with a memory are recommended as this allows your doctor to see all your blood pressure readings.
When measuring blood pressure, follow these rules:
Some people have high blood pressure when they visit a doctor’s office, but have normal blood pressure otherwise. This condition is called “white coat” hypertension. If your doctor thinks you have white coat hypertension, you may be asked to monitor your blood pressure at home or wear an ambulatory blood pressure monitor. An ambulatory blood pressure monitor is a small machine, about the size of a portable radio that you wear on your belt for 24 hours. This machine lets your doctor find out what your blood pressure was every 15 to 30 minutes. This information can help you and your doctor see the changes in your blood pressure during a normal day. Most people with white coat hypertension are not at higher risk of health problems, but they do require regular monitoring as they are more likely to develop true hypertension over time.
“Masked” hypertension is the opposite of “white coat hypertension. People with this condition have normal blood pressure in a doctor’s office, but have high blood pressure when elsewhere. If your doctor thinks you have masked hypertension, you may be asked to monitor your blood pressure at home or wear an ambulatory blood pressure monitor. People with “masked” hypertension are at higher risk for heart disease and stroke and may require medications to control their blood pressure.