Assuming an upright posture causes translocation of approximately 800 ml of blood from the intrathoracic venous compartment to veins of the buttocks, pelvis, and legs. The bulk of venous pooling occurs within the first 10 seconds and the total pooling is complete within three to five minutes.¹ The normal compensatory cardiovascular response to this orthostatic stress is a neurogenically mediated increase in heart rate and systemic vascular resistance. Patients with autonomic failure do not increase systemic vascular resistance, and the decrease in cardiac output during standing is also significant.¹ The resulting cerebral hypoperfusion causes postural lightheadedness, visual blurring, syncope, focal cerebral ischaemia, and even unexplained falls. In these patients orthostatic hypotension may be significantly exacerbated by prolonged recumbency, food or alcohol ingestion, physical exertion, and vasoactive drugs. Patient education directed at avoidance of these …