U.S. Lowers 'Normal' Levels for Blood Pressure Readings

The new category includes 45 million Americans whose blood pressure is 120 to 139 millimeters of mercury systolic (the top number) or 80 to 90 diastolic (the bottom number).

People with readings in this range do not need medication yet, but are quite likely to develop high blood pressure and so are advised to try to lower their pressure by losing excess weight, exercising more, quitting smoking, cutting back on salt and eating more fruits, vegetables and low-fat dairy products.

A statement issued by the National Heart Lung and Blood Institute said the new recommendations were based on studies showing that artery damage can begin even at blood pressure levels that until recently were thought to be normal. The risk of heart disease and stroke starts to rise at readings as low as 115/75, and doubles for each increase of 20/10 millimeters of mercury.