With the new guidelines, that patient will be "read the riot act" about exercise and healthy eating but the goal will be for them to bring their blood pressure down with those lifestyle changes before prescribing medications, Gandhi said.
Rather than 1 in 3 US adults having high blood pressure with the previous definition, the new guidelines will result in almost half of the USA adult population having the condition.
Harlan Krumholz, a cardiologist at Yale University, said the new definition will radically change how primary care doctors interact with their patients. One was tasked with lowering their systolic pressure (the first number, which measures the blood pressure when your heart pulses) to below 120, the other, to below 140.
The AHA says the new guidelines are created to help people address the potentially deadly condition much earlier.
High blood pressure has even associated dementia.
The category of prehypertension, referring to those with systolic pressure of 120-139, no longer exists.
Medication is recommended for people with stage 1 hypertension only "if a patient has already had a cardiovascular event such as a heart attack or stroke, or is at high risk of heart attack or stroke based on age, the presence of diabetes mellitus, chronic kidney disease or calculation of atherosclerotic risk". Then a person's reading becomes the average of those numbers and reduces the risk of "white coat hypertension" - blood pressure readings that are improperly elevated because a patient in a doctor's office is nervous.
"High blood pressure is called the silent killer because it usually has no signs or symptoms to go with it", says Dr. Calvin.
High blood pressure accounts for the second-largest number of preventable heart disease and stroke deaths in the United States, second only to smoking.
He added: "It is important, however, to realise that the change in the definition does not give course to increased prescriptions of medications".
Experts said the majority of Americans affected won't need medication but will need to make lifestyle changes.