Blood pressure is recorded as two numbers and written as a ratio: the top number, called the systolic pressure, is the pressure as the heart beats. The bottom number, called the diastolic pressure, is the measurement as the heart relaxes between beats. According to guidelines announced in November 2017 by the American Heart Association (AHA), people's blood pressure measurements fall into the following categories:
High blood pressure is classified as either primary (essential) high blood pressure or secondary high blood pressure. About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. Lifestyle factors that increase the risk include excess salt in the diet, excess body weight, smoking, and alcohol use. The remaining 5–10% of cases are categorized as secondary high blood pressure, defined as high blood pressure due to an identifiable cause, such as chronic kidney disease, narrowing of the kidney arteries, an endocrine disorder, or the use of birth control pills.
Stress reduction techniques such as biofeedback or transcendental meditation may be considered as an add-on to other treatments to reduce hypertension, but do not have evidence for preventing cardiovascular disease on their own. Self-monitoring and appointment reminders might support the use of other strategies to improve blood pressure control, but need further evaluation.