The new guidelines redefine hypertension as any reading that is 130/80 or above. Just three years ago, hypertension was diagnosed with a reading of 150/90.
This is the lowest threshold ever for assessing hypertension, and it means that half of all adults in the US suddenly have the problem. The new guideline, which has been announced by the American Heart Association, affects around 30 million Americans, who now have hypertension, and 2 per cent of whom—around 600,000 people—will need to start taking medication immediately.
The vast majority will be advised to change their diets and lifestyles in order to control their blood pressure.
Although hypertension has been called the 'silent killer' because of the damage it can cause to the heart and arteries, its definition has been a matter of fashion as much as science. Back in the 1980s, for instance, hypertension was diagnosed with a reading of 160/100 (the first number measures systolic pressure, when the heart contracts to pump blood, and the second is the diastolic, when the heart is at rest).