The word ‘Orthostasis’ means ‘upright posture’, and the word ‘hypotension’ means ‘low blood pressure’. Therefore, people with orthostatic hypotension suffer from symptoms of dizziness, faintness or lightheadedness only when they stand up after sitting or lying down, usually caused by low blood pressure. It can happen to anyone, and the effects are usually gone after a few seconds. Although it is very rare, spinning vertigo can be caused by orthostasis. If the dizziness persists, the patient may have long lasting orthostatic hypotension, which can be the symptom of a very serious problem.

Orthostatic hypotension is diagnosed using a tilt table test. Patients are strapped to a table and the table is tilted. Normal people have the ability to adjust to an upright position; there is no significant change in blood pressure. When people suffering from orthostatic hypotension undergo the test, it is seen that their pulse increases and their blood pressure drops. Tilt table testing, used during 1986, has been used to diagnose orthostatic hypotension. During tilt-table testing, a device called the Finometer keeps track of the haemodynamic (or blood pressure) changes in a noninvasive manner. In one particular study, algorithms were developed specifically to test the haemodynamic changes in the ‘head up’ position. These algorithms have been shown to accurately record the changes for further analysis.