TUESDAY, Oct. 30, 2018 (HealthDay News) -- When you're taking your blood pressure at home, a reading of 130 over 80 or above should be considered high, researchers report.

A reading of 120 over 80 is considered in the normal range.

"Most guidelines have recommended out-of-office monitoring for diagnosis of hypertension, but the normal limits of home blood pressure have not been accurately determined in the U.S. population," said study leader Dr. Wanpen Vongpatanasin. She is director of the Hypertension Fellowship Program at University of Texas Southwestern Medical Center in Dallas.

In the study, the researchers analyzed data on nearly 3,700 U.S. adults, aged 30 to 65. The finding matches guidelines issued in 2017 by the American College of Cardiology and the American Heart Association.

Co-author Dr. James de Lemos is a professor of internal medicine who holds a chair in cardiology at UT. "This study confirms the value of monitoring blood pressure at home as part of a comprehensive cardiovascular disease prevention strategy," he said in a university news release.

Nearly half of U.S. adults have high blood pressure. At-home blood pressure screening can better predict high blood pressure than a single measurement taken at a doctor's office, according to cardiologists.

This is due to a phenomenon called "white-coat syndrome," when blood pressure readings are higher when taken at the doctor's office due to patient anxiety, Vongpatanasin explained.

"Home blood pressure readings should be taken after resting quietly for five minutes. They should be taken multiple times, preferably twice a day over five to seven days with a minimum of two readings each time," Vongpatanasin said.

The study was published Oct. 29 in the journal Hypertension.

More information

The American Heart Association has more on blood pressure readings.