By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program
of the Cardiovascular Institute at Mount Sinai School of Medicine, New York.

Low blood pressure is less often a problem than high blood pressure, but there are some people (mostly elderly) who develop a rare problem called postural or orthostatic hypotension, in which the normal regulation of blood pressure is impaired. This results in very low blood pressure while standing (because the blood tends to pool in the legs) and high pressure when lying. The symptoms are dizziness and faintness when standing, and in severe cases loss of consciousness. These symptoms are relieved on lying down. In most cases it happens because of degeneration of the nerves that normally regulate the circulation (the sympathetic nerves), but it is occasionally seen in people who are treated with multiple blood pressure lowering drugs.