postural hypotension

A dramatic drop in blood pressure when you stand up. Postural hypotension may reduce blood flow to the brain and cause you to faint. Postural hypotension can happen to anyone for a variety of reasons, such as dehydration, lack of food, prolonged standing in the heat or being generally run down. Aging, medication or psychological factors can also influence it. Postural hypotension occurs most often in people who are taking drugs to control high blood pressure.