As noted earlier, blood pressure varies considerably during the course of an average day. It also varies
according to age—a baby’s blood pressure may normally be 70/50, whereas the average blood pressure
in an adult is about 120/80. Until recent years, there was no clear agreement among physicians as
to what constituted high blood pressure, but now it is generally agreed that blood pressure readings that
are consistently above 140/90 warrant a diagnosis of hypertension, and the higher the readings, the more
serious the disease. (See Table 12.1.) A reading of about 140/90 does not necessarily indicate that the
condition requires immediate therapy, but it does suggest follow up and some treatment.