There were other applications proposed in the early days of the. Internet, including packet based voice communication (the. precursor of Internet telephony), various models of file and disk. sharing, and early âwormâ programs that showed the concept of. agents (and, of course, viruses). A key concept of the Internet is.
View All. For a long time, normal blood pressure was defined as 120/80 mm Hg (systolic/diastolic). Recently, however, the American Heart Association revised its guidelines about what an optimal blood pressure range is, and when blood pressure is considered too high or too low. While 120/80 used to be considered normal, the new guidelines define three levels of abnormal blood pressure values. 120-139 / 80-89 is now considered to be âprehypertensionâ (or âalmost high blood pressure), and doctors are watching blood pressures in this range more carefully than in the past.
A normal systolic pressure is below 120. A reading of 140 or more is high blood pressure (also called hypertension). The diastolic reading, or the bottom number, is the pressure in the arteries when the heart rests between beats. This is the time when the heart fills with blood and gets oxygen. A normal diastolic blood pressure is lower than 80. 90 or higher is high blood pressure. Our charts below have more details.