People who feel faint, dizzy or lightheaded when standing up may be experiencing a sudden drop in blood pressure called orthostatic hypotension. Now a new study in the U.S. says middle-aged people who experience such a drop may have a greater risk of developing dementia or stroke decades later. Orthostatic hypotension has previously been linked to heart disease, fainting and falls. For this study, low blood pressure upon standing was defined as a drop of at least 20 millimeters of mercury (mmHg) in systolic blood pressure, which is the pressure in the blood vessels when the heart beats, or at least 10 mmHg in diastolic blood pressure, the pressure when the heart is at rest. Normal blood pressure is less than 120/80 mmHg. The study involved 11,709 people with an average age of 54 who were followed for an average of 25 years. Participants met with researchers up to five times over the course of the study. None had a history of heart disease or stroke at the beginning of the study. The findings have been published in the journal, Neurology .
