Only continuous beat-to-beat BP measurement during an active standing-up maneuver can document this condition.Classic orthostatic hypotension is frequently characterized by a systolic blood pressure decrease of ≥20 mmHg or diastolic blood pressure decrease of ≥10 mmHg between 30 seconds and 3 min of standing.Delayed orthostatic hypotension is frequently characterized by a sustained systolic blood pressure decrease of ≥20 mm Hg or a sustained diastolic blood pressure decrease ≥of 10 mm Hg beyond 3 minutes of standing or upright tilt table testing. Management
Lifestyle changes
Apart from treating underlying reversible causes (e.g., stopping or reducing certain medications, treating autoimmune causes), several measures can improve the symptoms of orthostatic hypotension and prevent episodes of syncope (fainting). Even small increases in the blood pressure may be sufficient to maintain blood flow to the brain on standing.In dysautonomic patients who do not have a diagnosis of high blood pressure, drinking 2–3 liters of fluid a day and taking 10 g of salt can improve symptoms, by maximizing the amount of fluid in the bloodstream. Another strategy is keeping the head of the bed slightly elevated. This reduces the return of fluid from the limbs to the kidneys at night, thereby reducing nighttime urine production and maintaining fluid in the circulation. Various measures can be used to improve the return of blood to the heart; the wearing of compression stockings and exercises ("physical counterpressure maneuvers" or PCMs) can be undertaken just before standing up (e.g., leg crossing and squatting).
alpha blockers), autonomic neuropathy, decreased blood volume, multiple system atrophy,  and age-related blood-vessel stiffness. Apart from addressing the underlying cause, orthostatic hypotension may be treated with a recommendation to increase salt and water intake (to increase the blood volume), wearing compression stockings, and sometimes medication (fludrocortisone, midodrine, or others). Salt loading (dramatic increases in salt intake) must be supervised by a doctor, as this can cause severe neurological problems if done too aggressively. Signs and symptoms
Orthostatic hypotension is characterized by symptoms that occur after standing (from lying or sitting), particularly when done rapidly. Many report lightheadedness (a feeling that one might be about to faint), sometimes severe, or even actual fainting with associated fall risk. With chronic orthostatic hypotension, the condition and its effects may worsen even as fainting and many other symptoms become less frequent. Generalized weakness or tiredness may also occur. Some also report difficulty concentrating, blurred vision, tremulousness, vertigo, anxiety, palpitations (awareness of the heartbeat), unsteadiness, feeling sweaty or clammy, and sometimes nausea. A person may look pale. Some people may experience severe orthostatic hypotension with the only symptoms being confusion or extreme fatigue. Chronic severe orthostatic hypotension may present as fluctuating cognition/delirium. Women who are pregnant are also susceptible to orthostatic hypotension. Associated diseases
The disorder may be associated with Addisons disease, atherosclerosis (build-up of fatty deposits in the arteries), diabetes, pheochromocytoma, porphyria, and certain neurological disorders, including  autoimmune autonomic ganglionopathy, multiple system atrophy, and other forms of dysautonomia. It is also associated with Ehlers–Danlos syndrome and anorexia nervosa.