MONDAY, Dec. 20, 2004 (HealthDayNews) -- When done properly, blood pressure monitoring by people at home may be the best way to gauge daily levels, according to new guidelines issued by the American Heart Association.
However, the association warns that rising obesity rates mean too many Americans are using home blood pressure monitors with arm cuffs that are too small, potentially skewing their readings.
While readings taken in a doctor's office still have an important role to play in monitoring hypertension, "home blood pressure monitoring tends to reflect more closely the day-to-day blood pressure readings that people have," explained Dr. Daniel Jones, a co-author of the new guidelines and dean of the school of medicine at the University of Mississippi.
Heart association experts last issued blood pressure management recommendations in 1993; the updated guidelines appear in the Dec. 21 issue of Hypertension.
According to the association, nearly one in three U.S. adults -- about 65 million people -- have high blood pressure, defined as a consistent systolic pressure of 140 mmHg or above and a diastolic pressure at or above 90 mmHg. Millions more may fall into the "pre-hypertension" category, with systolic readings between 120-139 mmHg and diastolic readings between 80-89 mmHg.
Since the 1980s, patient home monitoring of blood pressure using store-bought devices has become more accepted in the detection and management of high blood pressure. As Jones explained, measurement of blood pressure at home may be more accurate than in the doctor's office, since readings tend to rise in the presence of health-care workers.
"Almost everyone has what we call the 'white-coat effect' when they go into a physician's office -- a response our brains have to being in a nervous situation," he said. "Home monitoring allows the measurement of blood pressure in an atmosphere that more closely measures daily activity."
More and more studies in the last decade have confirmed that a combination of home and office monitoring is the best means of getting an accurate picture of hypertension risk, Jones said.
"There's been lots of new data that has been meaningful about home blood pressure monitoring," he said. "That's reflected in these new guidelines."
The new guidelines strongly support home monitoring, as long as it's done properly, Jones said. Appropriate arm cuff size remains a key component in any home blood pressure reading, Jones said.
"There's a strong emphasis on proper cuff size in the recommendations, because of the growing problem of obesity in this country," Jones explained. "More and more, as our bodies get bigger our arms get bigger, too, so larger and larger percentages of people need a larger-sized cuff for accurate measurement."
He said that decisions on the timing and method of home blood pressure monitoring is best left up to a patient and his or her doctor. However, in a statement, the heart association recommends that "ideally, blood pressure should be taken after several minutes' relaxation, when a person is comfortably seated in a chair, legs uncrossed, not talking, back and arm supported, and the cuff placed on bare skin."
Jones said the heart association does not endorse any particular brand of home monitor, but it does recommend that devices carry the seal of approval of the Association for the Advancement of Medical Instrumentation (AAMI). The U.S. Food and Drug Administration delegates testing and certification of home blood pressure monitors to the AAMI, Jones said.
He stressed the new recommendations don't in any way diminish the importance of blood pressure readings taken in a physician's office. "Office blood pressure measurement is a critical part of what's necessary for the good management of blood pressure problems," Jones said.
To learn more about hypertension, visit the American Heart Association.