A high pressure of 80mmHg and a low pressure of 40mmHg is an abnormal blood pressure. Normal blood pressure fluctuates between 90-140mmHg systolic and 60-90mmHg diastolic. 80mmHg systolic and 40mmHg diastolic is obviously hypotension, it is recommended that the patient seek medical attention and further check ECG or 24-hour ambulatory ECG, ambulatory blood pressure, cardiac ultrasound, etc. Patients are advised to seek medical attention in a timely manner to clarify the cause of hypotension, and timely treatment is very important to bring blood pressure back to normal as soon as possible. Analysis of many causes of hypotension, including physical weakness, especially the elderly or patients with previous hypertension, coronary artery disease, myocardial infarction, cardiac insufficiency, arrhythmia, are more likely to show low blood pressure. A state of low blood pressure is also likely to occur in summer when sweating is high and hydration is not timely, or in cases of cold, fever, acute gastroenteritis, or diarrhea. Active treatment of the primary disease is beneficial to maintain stable blood pressure.