The ideal range of normal blood pressure in humans is <120 mmHg systolic and ≤80 mmHg diastolic, so a blood pressure <120/80 mmHg is the ideal blood pressure. Hypertension can be diagnosed if the systolic blood pressure is ≥ 140 mmHg and the diastolic blood pressure is ≥ 90 mmHg. However, the diagnosis of hypertension must emphasize that it is measured 3 times on non-same day, which means that the blood pressure should be measured at least 3 times, and not on the same day. A systolic blood pressure ≥ 140 mmHg and a low pressure ≥ 90 mmHg is hypertension. The diagnostic criteria for hypertension are artificially set, and the US guidelines have revised the new criteria for the diagnosis of hypertension, and they believe that a systolic blood pressure ≥ 130 mmHg and a diastolic blood pressure ≥ 80 mmHg is hypertension, which suggests that hypertension is more dangerous. If the systolic, or high, pressure is ≤90 mmHg, it is called hypotension. In fact, most cases of hypotension are more critical, such as low blood pressure due to some diseases, and some people show signs of shock. Sometimes the electronic blood pressure measurement is not always accurate. Sometimes the electronic blood pressure shows about 80 mmHg, but there are no other symptoms such as dizziness, which may be a measurement error. Most normal people's blood pressure is usually above 90mmHg, if it is ≤90mmHg, there may be some other reasons. Of course, if you have symptoms such as dizziness, nausea, or vomiting, you should go to the hospital as soon as possible for treatment. If there are no symptoms, it may not need to be treated. Blood pressure that is relatively low for a long time and asymptomatic is mostly considered a better sign. Because many heart-protective drugs have a hypotensive effect, many diseases are caused by high blood pressure.