The term blood pressure describes the force it takes for your heart to pump blood through your body. Normal blood pressure is a sign of good cardiac health. High blood pressure — also called hypertension — means your heart has to work too hard to accomplish this vital task.

Two figures comprise blood pressure. The first measure is the force exerted against the vessel walls as blood flows from the heart into the arteries; it is called the systolic blood pressure and is represented as the top number in a blood pressure reading.

The second figure, called diastolic blood pressure, is the force against the walls of blood vessels as your heart rests between beats.

These two values are expressed in a ratio of systolic over diastolic measurements. Blood pressure ranges include:

• Normal: Less than 120 over 80 (120/80)

• Elevated: 120 to 129 over 80 to 89

• Stage 1 high blood pressure: 130 to 139 over 80 to 89

• Stage 2 high blood pressure: 140 or higher over 90 or higher

• Hypertensive crisis: More than 180 over more than 120 (In this case, you should consult a doctor immediately.)

In people over age 60, a healthy blood pressure should be 140 over 90 or below. This is also the normal reading for people of any age with diabetes or chronic kidney disease.

In addition, there are two types of high blood pressure: primary and secondary. Primary (or essential) high blood pressure is hypertension that doesn’t have a known cause; it accounts for most cases. Secondary high blood pressure, which is less common, occurs as the result of an underlying medical condition that when corrected, can cause blood pressure to normalize.