Postural hypotension, also called orthostatic hypotension, is a sudden and exaggerated reduction in blood pressure that happens in some people when they stand up. Symptoms can include light-headedness, blurry vision, leg weakness, and sometimes, passing out.

Postural hypotension is more common in older adults and may be caused by volume depletion (e.g., dehydration), certain medications, and an underlying nervous system condition.

This article explores what it means to have postural hypotension, including its symptoms, causes, diagnosis, and treatment. It will also review complications of postural hypotension and provide guidance on when to seek medical attention.

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Postural Hypotension Symptoms

Postural hypotension symptoms manifest rapidly when a person goes from lying down to sitting up or from sitting to standing.

Symptoms result from a sudden blood pressure drop, leading to cerebral hypoperfusion (poor blood flow to the brain).

Symptoms may be aggravated by carbohydrate-rich meals, exercise, prolonged bed rest, and hot weather. They also tend to be more pronounced in the early morning.

Hallmark postural hypotension symptoms include:

  • Light-headedness or dizziness
  • Blurry or dimmed vision
  • Confusion
  • Unusual tiredness
  • Leg buckling or weakness
  • Fainting (syncope) in severe cases

Interestingly, in some cases, poor blood flow to the shoulder and neck muscles results in pain in the neck, shoulder, and base of the skull—a phenomenon called coat-hanger headache.

Less commonly, hypoperfusion to the lungs and heart may cause trouble breathing (dyspnea) or chest pain (angina).

Postural Hypotension Causes

Postural hypotension has many causes, generally divided into the following three categories:



Hypotension

Intravascular Volume Depletion

Intravascular volume depletion (hypovolemia) means insufficient fluid is circulating in the body's blood vessels, leading to a drop in blood pressure.

Intravascular volume depletion may occur if a person is dehydrated, such as from being sick with a fever or experiencing severe diarrhea or vomiting. Sweating from strenuous exercise and simply not drinking enough fluids can also lead to dehydration.

Intravascular volume depletion may also occur if a person is bleeding, taking diuretics (sometimes referred to as water pills), or has heart failure.

Medications

Some medications may cause orthostatic hypotension by impairing the autonomic nervous system response, a phenomenon called dysautonomia.

The autonomic nervous system (ANS) is a network of nerves responsible for regulating body functions that are out of a person's control, like heartbeat, blood pressure, breathing, and digestion.

These medications include:

  • High blood pressure medications, particularly vasodilators like hydralazine and minoxidil
  • Antidepressants, especially tricyclic antidepressants
  • Antiparkinsonian drugs like levodopa, dopamine agonists like Mirapex (pramipexole), and anticholinergics like Cogentin (benztropine) and Artane (trihexyphenidyl)

Neurogenic Causes

Neurogenic orthostatic hypotension happens when there is a diminished release of norepinephrine from nerves within the sympathetic nervous system.

Norepinephrine is a chemical messenger (neurotransmitter) that constricts (tightens) blood vessels during stress.

The sympathetic nervous system is part of the autonomic nervous system, regulating the body's flight-or-fight response during perceived danger.

As a result of reduced norepinephrine release, blood pressure drops after standing because blood vessels cannot constrict and compensate for the gravity-related pooling of blood in the legs.

Examples of nervous system conditions associated with neurogenic orthostatic hypotension include:

  • Parkinson's disease results from the death of dopamine-producing nerve cells in the area of the brain that controls movement, resulting in hallmark motor (movement-related) symptoms like shaking, stiffness, and walking problems.
  • Dementia with Lewy bodies develops from a buildup of protein deposits (Lewy bodies) in the brain, leading to memory and thinking problems.
  • Guillain-Barré syndrome (GBS) occurs when a person's immune system attacks peripheral nerves, causing mild to severe muscle weakness.
  • Familial dysautonomia (FD), also called Riley-Day syndrome, is a rare inherited condition that affects the development and survival of autonomic nervous system cells.

Neurogenic orthostatic hypotension can also result from non-nervous system diseases that impair autonomic nerve functioning. Conditions possibly triggering secondary neurogenic orthostatic hypotension include diabetes, alcohol use disorder, chronic kidney disease, amyloidosis, autoimmune diseases, and vitamin B12 deficiency.

How Is Postural Hypotension Diagnosed?

Postural hypotension is evaluated by taking a person's blood pressure while sitting or lying down and then again after standing up. The measurements must be taken within three minutes.

A sustained reduction of at least 20 millimeters of mercury (mm Hg) of systolic blood pressure and/or 10 mm Hg of diastolic blood pressure confirms a diagnosis of postural hypotension.

What Is Systolic and Diastolic Blood Pressure?

The systolic pressure (top number) indicates the force exerted against artery walls when the heart beats. The diastolic pressure (bottom number) indicates the force exerted against artery walls when the heart rests between beats.

To determine if there is a treatable cause for a person's postural hypotension, a healthcare provider will perform a thorough medical and family history and physical examination.

For example, they will ask for a medication list and inquire about previously diagnosed health conditions like heart or kidney disease, diabetes, and alcohol use disorder.

In addition, other autonomic nervous system failure symptoms will be asked about, like erectile dysfunction, bladder problems, and constipation.

Further diagnostic testing may also be performed. Examples of other tests include:

Other tests, like a tilt table test (being monitored when strapped to a table that moves in different positions) or the Valsalva maneuver ( a breathing technique),may be performed to confirm a diagnosis, particularly if a person has delayed orthostatic hypotension (blood pressure changes occur within three to 10 minutes of standing).

A tilt table test can also help evaluate alternative diagnoses, namely postural orthostatic tachycardia syndrome (POTS).

What Is POTS?

POTS is a disorder of orthostatic intolerance, an abnormal autonomic nervous system response when moving from sitting to standing.

Symptoms are similar to postural hypotension, although there is little to no drop in blood pressure. Also, excessive tachycardia (a fast heart rate) occurs upon standing.

Does Postural Hypotension Go Away?

Postural hypotension may go away if the underlying cause is reversible.

For example, stopping or reducing the dose of an offending medication or drinking ample fluids (if dehydration is the culprit) can effectively reverse the postural hypotension.

In other cases, especially with neurogenic orthostatic hypotension, treating the underlying disease and adopting certain lifestyle behaviors can help manage the condition. Sometimes, medications are prescribed to lessen symptoms.

Postural Hypotension Treatment

Treating non-reversible causes of postural hypotension begins with lifestyle or nondrug treatments. If these fail to reduce symptoms, medication may be added.

Lifestyle Behaviors

The following lifestyle habits may help reduce episodes and symptoms of postural hypotension:

  • Elevating the head of the bed at night and rapidly drinking water (over two to three minutes) before getting out of bed in the morning.
  • Drinking plenty of fluids daily and avoiding consuming large, heavy meals.
  • Limiting alcohol intake
  • Standing up slowly from a lying or seated position.
  • Avoiding aggravating factors like warm weather, hot showers, rapidly standing up, or prolonged bed rest.

Adding salt to your diet—around 1 to 2 teaspoons a day—may also be helpful, as salt leads to a transient, slight increase in blood pressure when seated or standing up.

That said, long-term use of salt increases the risk of cardiovascular disease, and this practice should be avoided in people with certain medical conditions, namely heart failure. Please weigh the risks and benefits of salt intake with a healthcare provider.

Lastly, a healthcare provider may also recommend wearing compression stockings on the legs and a compression device around the belly (abdominal binder). These devices generate pressure against the lower body, increasing blood flow in the legs. 

Medications

Various medications may be prescribed to treat postural hypotension.

Midodrine

Midodrine is an oral (by mouth) medication that, after entering the body, is converted into desglymidodrine. This agent stimulates alpha-adrenergic receptors within the muscular walls of blood vessels, causing the vessels to narrow, thereby increasing blood pressure.

Midodrine's effects occur within around one hour of taking it and last about four hours. The drug is given three times daily, every four hours (e.g., an example dosing schedule is 8 a.m., noon, and 4 p.m.).

A major downside of midodrine is it's associated with a sixfold increased risk of supine hypertension (high blood pressure when lying down). Avoiding lying down after taking midodrine for a few hours is advised.

Droxidopa

Droxidopa is an oral medication converted into norepinephrine after entering the body. Increased norepinephrine levels in the body constrict blood vessels, raising blood pressure.

Droxidopa is given two to three times per day, and doses range from 100 milligrams (mg) to 600 mg.

Like midodrine, droxidopa may cause supine hypertension, although the risk appears lower.

Fludrocortisone

Unlike midodrine and droxidopa, fludrocortisone is not Food and Drug Administration (FDA)–approved to treat postural hypotension; however, it's sometimes prescribed to treat the condition, particularly in the short term.

Fludrocortisone works by increasing the absorption of salt and water in the kidneys, which increases intravascular volume and blood pressure. Potential side effects include low potassium blood levels (hypokalemia) and supine hypertension.

Can You Prevent Postural Hypotension?

Postural hypotension cannot necessarily be prevented unless the cause is reversible.

If you have postural hypotension, you may engage in lifestyle changes to help minimize symptoms, such as staying hydrated, getting up slowly, avoiding hot weather, or wearing compression stockings. A healthcare provider may prescribe medication if these changes fail to ease your symptoms.

Orthostatic Hypotension vs. Orthostatic Hypertension

Orthostatic hypertension is an increase in systolic blood pressure by 20 mm Hg or more (with a baseline systolic blood pressure of 140 mm Hg) when standing.

On the other hand, orthostatic hypotension is a decrease in systolic blood pressure by 20 mm Hg or more and/or a drop in diastolic blood pressure by 10 mm Hg.

In summary, the critical difference between these two phenomena is that orthostatic hypertension is a high blood pressure disorder, and orthostatic hypotension is a low blood pressure disorder.

Postural Hypotension Complications

Postural hypotension is associated with numerous complications, namely falls, which can cause bone breaks (fractures) and head injuries.

Cognitive impairment (thinking and memory problems) is also linked to postural hypotension. It's unclear if treating postural hypotension can prevent or delay cognitive decline.

Likewise, postural hypotension is strongly associated with cardiovascular disease, including an increased risk of stroke, heart failure, heart attack (mixed results), and death.

When to See a Healthcare Provider

Symptoms of postural hypotension, like light-headedness, may occur now and then when standing after lying down or sitting for a long time (especially if you are an older adult or mildly dehydrated). However, speak to a healthcare provider if you notice symptoms worsening or becoming more frequent.

Also speak to a healthcare provider if you fall and hit your head or injure another body part.

Call 911 or go to your nearest emergency room if you are experiencing stroke symptoms or heart attack symptoms, such as pain or discomfort in the center or left side of the chest or trouble breathing.

Summary

Postural hypotension, or orthostatic hypotension, is a drop in blood pressure when going from lying to sitting or from sitting to standing. Symptoms are caused by low blood pressure, which results in poor blood flow to the brain, triggering dizziness, blurry vision, and sometimes, fainting.

There are three causes of postural hypotension—low blood volume (e.g., dehydration or anemia), medication-induced, and nervous system disorders like Parkinson's disease.

After the underlying cause is addressed, treatment of postural hypotension involves lifestyle changes (e.g., drinking ample water and wearing compression stockings). Some people require medication to alleviate symptoms and help prevent complications like falls.

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