People with low blood pressure are themselves prone to lower pulse pressure difference, but the normal pulse pressure difference is around 40mmHg, as long as it is between 20-40mmHg, it is a normal pulse pressure difference, and patients do not have to worry too much. For the cause, it is mainly due to benign low blood pressure that occurs due to physical constitution or genetic factors, in this case it is not harmful to people. Low blood pressure due to chronic diseases or physical weakness, the harm in this case, mainly prone to dizziness, black blindness, or even a transient loss of consciousness when the body position changes, failure to lead to secondary injuries. Some low blood pressure is caused by oral medications, such as psychiatric drugs or α-blockers, etc., can cause low blood pressure, as well as long-term diabetic people, hypertensive people, in the oral antihypertensive drugs, due to autonomic dysfunction, will also appear postural hypotension. Postural hypotension is harmful to people, and is prone to ischemia or blackout and fainting of such organs.