You can, with care and supervision, do a rough-and-ready test at home for orthostatic intolerance: the ‘poor man’s tilt test’. This will give you an indication of whether you are likely to have orthostatic intolerance.
Formal, more reliable diagnosis of orthostatic intolerance is done in a clinical setting using a ‘tilt table test’ in which a patient lies flat on a table which is then tilted through about 70 degrees until it is almost vertical. The table has a footplate that takes the patient’s weight in this position.
The patient remains completely immobile while their heartrate and blood pressure are monitored, usually until the point at which they develop symptoms.
See also Dr. Natelson’s test for Postural Orthostatic Syndrome of Hyperventilation.
It can be difficult, and take much persistence, to get a clinical diagnosis of orthostatic intolerance. Even doctors who are familiar with Postural Orthostatic Tachycardia Syndrome (POTS), which produces fairly immediate and obvious symptoms, may not know about delayed orthostatic intolerance (neurally mediated hypotension, or NMH) which has less obvious symptoms and takes longer to develop.
Dysautonomia sites may be helpful in locating a suitable specialist (see our Resources page).