Under new guidelines from the American Heart Association, nearly half of all adults in the United States have high blood pressure.

"It's called a silent killer for a reason," says Dr. Chris Paris, of Brookdale Hospital. "You don't feel it. What I often tell patients is that when you start feeling hypertension, the game's over."

The old standard listed a reading above 140 over 90 as high blood pressure. The new guideline lowers that to 130 over 80.

People with readings of 120 over 80 are still considered normal.

High blood pressure can lead to strokes, heart disease and kidney failure, Dr. Paris says.

Ways to lower blood pressure include reducing salt intake, eating potassium-rich foods and working out.

Your life could depend on it.