Heightened alert--the standards for blood pressure have changed.

Hypertension, or high blood pressure, as it is more commonly known, is a widespread health problem that shows no sign of going away. Part of the reason for this, is that it is an invisible disease that many people don't realize they have. They suffer no symptoms, and feel no different--so why worry?

But while there are little or no symptoms, high blood pressure can lead to serious health problems. High blood pressure is a condition associated with the narrowing of the arteries. This narrowing causes blood to be pumped with excessive force against the artery walls overworking the heart. If left untreated, hypertension will eventually burden your kidneys, destroy the elasticity of your circulatory system, and weaken and enlarge your heart, thereby decreasing its pumping power.

A blood pressure reading is made up of two numbers and is measured in millimeters of mercury. The top number refers to systolic blood pressure, which is measured while the heart contracts and pumps blood into the arteries. The bottom number refers to diastolic blood pressure, which is measured while the heart fills with blood. A person with systolic and/or diastolic blood pressures consistently above the normal range (120/80 mm Hg) is said to have high blood pressure.

"It's a silent killer and is so common that it's become somewhat of an epidemic," says Afshine Emrani, M.D., a cardiologist at Encino-Tarzana Regional Medical Center.

High blood pressure may be silent, but is not being ignored. For the first time in 6 years, a revised national classification system announced in May 2003 toughens blood pressure guidelines. So what once was considered safe, is now considered pre-hypertensive. The new pre-hypertension classification is a blood pressure reading of 120-139 over 80-89. Only a blood pressure reading of less than 120 over 80 is now considered normal, putting a rather large group of people on higher alert.

"Pre-hypertensive is like another new classification, pre-diabetic, which tells you you are more likely to become diabetic if you don't take certain steps," says Emrani. "The new classification is a warning to patients that if they keep going in that direction they'll end up needing medical therapy. We've entered an era of 'pre-disease,' which allows more time for preventative measures."

If you are diagnosed as pre-hypertensive, the simplest thing you can do is modify your lifestyle. Begin exercising on a regular basis, loose those extra pounds, restrict sodium intake and eat a healthy diet high in fruits and vegetables. Following these familiar guideposts may keep you from requiring pharmacological intervention.

Be proactive about preventing the complications that can result from undiagnosed and unmanaged hypertension.

This article was provided by Encino-Tarzana Regional Medical Center's San Fernando Valley Heart Institute. For more information, or to see a heart specialist, call 1-800 CARE NOW.