If you have ever been to see a doctor, then you have had your blood pressure taken, usually by a nurse before your appointment begins. You might have to remove your arm from a bulky sleeve and sit with your legs uncrossed in front of you. The healthcare professional then places a cuff around your upper arm and inflates it. As the arm cuff slowly deflates, he or she will listen to your pulse with a stethoscope while watching a gauge on the cuff which measures the pressure inside your veins in a scale of units called millimeters of mercury (mmHg). Home blood pressure measuring devices and those at pharmacies use the same basic principles to measure blood pressure.
When finished, you will have your blood pressure reading given to you as two numbers, for example 120/70 mm Hg (read: 120 over 70 millimeters of mercury). To understand what your blood pressure readings mean, you need to know a little anatomy, the difference between the two numbers and also which readings would be considered low, normal or high.
What’s What? Understanding Systolic and Diastolic Numbers
When your heart beats, it pushes blood through your arteries and veins, delivering the oxygen and nutrients your body’s cells need to function. Respectively, the systolic and diastolic numbers record the amount of pressure your blood exerts onto the walls of your arteries when the heart pumps and when it relaxes between beats.
- The Top Number: Systolic pressure, measured on the heartbeat
- The Bottom Number: Diastolic pressure, measured between beats
With age, a person’s systolic blood pressure will steadily rise due to the long-term build up of plaque, large arteries which begin to harden and the increasing frequency of age-related cardiovascular disease. A high systolic number is usually considered more serious than a high diastolic number. Both, however, can be serious and should be addressed. According to the American Heart Association, “the risk of death from ischemic heart disease and stroke doubles with every 20 mm Hg systolic or 10 mm Hg diastolic increase among people from age 40 to 89.”
How Does Your Reading Compare?
On its own, your blood pressure reading doesn’t mean much. To understand how it relates to your health and if you have low, normal or high blood pressure (hypertension), you must compare your reading to a chart. The American Heart Association recognizes the following four blood pressure categories:
- Normal – Less than 120/80 mm Hg
- Elevated – 120 to 129 mm Hg systolic and below 80 diastolic
- Hypertension Stage 1 – 130 to 139 mm Hg systolic or 80 to 89 mm Hg diastolic
- Hypertension Stage 2 – 140/90 mm Hg or higher
- Hypertensive Crisis (requires medical attention) – Readings exceed 180/120 mm Hg
Before you can categorize your blood pressure, take a range of readings, using an at-home device to measure blood pressure at different times of day, after different levels of activity and before and after mealtimes. Now that you understand what blood pressure readings mean, talk with your doctor about steps you can take to lower your blood pressure and prevent future heart problems.