You could have high blood pressure and not even realize it.

Anyone with blood pressure higher than 130/80 is considered to have hypertension, according to new joint guidelines from the American Heart Association and American College of Cardiology.

Nearly half of all Americans are now at risk. The threshold for high blood pressure used to be when the top number hit 140 or higher.

The president of the American Medical Association says the best thing to do is get tested now.

"So we need people to know that they need to know their numbers. You can't tell by the way you feel. You have to check your blood pressure. So we encourage them to partner with their doctor to know their numbers to develop a plan for treating their high blood pressure," said David Barbe.

According to the AMA, blood pressure of 120/80 is now even considered to be elevated.

Aside from blood pressure-lowering medication- doctors recommend exercising and watching what you eat.