What is Postural Hypotension?
A. Postural or orthostatic hypotension is characterized by a fall of blood pressure on standing up, which if unchecked, may lead to a loss of consciousness. It is not common, and it mainly occurs in older people. It is caused by a deterioration of the blood pressure-regulating mechanisms. Normally when we stand up our blood pressure changes very little, because the arteries and veins in our legs constrict, and prevent the blood from pooling in the legs. This happens as a result of a reflex controlled by the brain and the sympathetic nervous system, and it’s the sympathetic nerves that make the vessels contract. If the sympathetic nerves are not working properly, as is the case in postural hypotension, the blood tends to pool in the legs on standing, and fainting occurs because there is not enough blood left in the system to keep the brain properly perfused. When people with postural hypotension are horizontal for long periods of time, their blood pressure may go too high.
