Orthostasis means upright posture, and hypotension means low blood pressure. Thus, orthostatic hypotension consists of symptoms of dizziness, faintness or lightheadedness that appear on standing, and are caused by low blood pressure. Only rarely is spinning vertigo caused by orthostasis. Symptoms that often accompany orthostatic hypotension include chest pain, trouble holding the urine, impotence, and dry skin from loss through sweating.
Blood pressure is maintained by a combination of several factors.
The heart is the central pump, and a weak or irregular heart can cause orthostasis. Conditions such as arrhythmia, heart failure, deconditioning, and pregnancy are examples where the heart may not be able to provide an adequate blood pressure. Numerous medications affect blood vessels including most of the medications used for blood pressure and many of the medications used in psychiatry and for anginal heart pain. Heat, such as a hot shower or from a fever, can also dilate blood vessels and cause orthostasis. The nervous system senses and responds to regulate blood pressure.