Postural orthostatic tachycardia syndrome (POTS) is characterized by an exaggerated heart rate response to the standing position in a patient with symptoms of orthostatic intolerance. It is likely a heterogeneous disorder representing a common manifestation of a number of possible underlying derangements such as impaired sympathetically mediated vasoconstriction, excessive sympathetic drive, volume dysregulation and deconditioning. While the actual prevalence of POTS is unknown, it has been estimated to affect at least 500,000 individuals in the United States. It predominately affects young individuals, and particularly women.