NBC - A new government study finds nearly a third of American adults have hypertension, with less than half having it under control.

Statistics from the National Center for Health Statistics show the rate of high blood pressure has not gone up in the past decade, but it has not gone down either. Hypertension rates are stagnant.

"When you have high blood pressure that's not adequately treated, then you're at greater risk of having a heart attack, stroke, heart failure and kidney failure. And that's particularly true for our African American population," says Dr. Angela L. Brown of Washington University School of Medicine in St. Louis.

Doctors say hypertension often comes on at an earlier age among black men and women and tends to be more difficult to treat.

LaZondra Griggs is a success story. After living with uncontrolled high blood pressure for more than a decade, she's now on the right medications and exercising five days a week.

Family history certainly played a role in LaZondra Griggs' hypertension.

"My grandmother had it, and my mother had it, and they're both deceased. So.. it was very important for me to get mine under control," says Griggs.

The target blood pressure for most healthy adults is less than 140 over 90.

Read more: http://on.today.com/2yw2QDU