What blood pressure and the numbers mean

Blood pressure is the force of blood against the walls of arteries. High blood pressure, called hypertension, makes the heart work too hard and can lead to heart disease, stroke, kidney disease and other problems.

Systolic pressure, the first number in a blood pressure reading, is considered normal at 120 or below. Diastolic pressure, the second number, should be 80 or below. Readings of 140/90 or higher indicate high blood pressure.

Since last year, researchers have classified blood pressure levels between 120/80 and 139/89 as prehypertension, or elevated blood pressure that is likely to lead to hypertension.

High blood pressure has no symptoms, so people probably won’t know they have it unless they take a blood pressure test or become seriously ill.

A new study estimates that 29 percent of American adults have hypertension, and 31 percent have prehypertension. Blood pressure tends to increase as people get older.

To prevent high blood pressure, experts advise people to maintain a healthy weight, be physically active, eat a healthy diet, limit intake of salt and sodium and avoid excessive drinking.

Many different medications treat high blood pressure. They can slow heartbeats, widen arteries and flush excess sodium from the body. Sometimes doctors treat patients with a combination of drugs.