Postural Orthostatic Tachycardia Syndrome (POTS)

Postural Orthostatic Tachycardia Syndrome (POTS) is a form of autonomic nervous system dysfunction that affects how the body regulates heart rate and blood flow when moving to an upright position. Instead of maintaining steady circulation, the heart rate rises abnormally upon standing, causing symptoms such as dizziness, lightheadedness, fatigue, and palpitations. With proper evaluation and management, many people can significantly improve their quality of life.

What is Postural Orthostatic Tachycardia Syndrome?

Postural Orthostatic Tachycardia Syndrome (POTS) is a disorder of autonomic regulation, the system that controls involuntary functions like heart rate and circulation. In POTS, the body does not properly compensate for upright posture. When standing, blood tends to pool in the lower body, limiting the amount returning to the heart. To maintain adequate circulation, the heart rate increases by 30 beats per minute (or 40 bpm in teenagers) or more within 10 minutes of standing.

This characteristic rise in heart rate occurs without a significant drop in blood pressure, which is a key distinction between POTS and orthostatic hypotension.

Causes & Symptoms of Postural Orthostatic Tachycardia Syndrome

The exact cause of POTS is still being studied, and the condition can look slightly different from person to person. Current research shows that POTS is often multifactorial, involving several contributing mechanisms. Symptoms typically intensify upon standing and may fluctuate throughout the day.

Postural Orthostatic Tachycardia Syndrome (POTS) Causes:

Autonomic Nervous System Dysfunction
In many individuals, there is impaired constriction of blood vessels upon standing. This allows blood to pool in the legs and abdomen, reducing circulation back to the heart.
Neuropathic Changes

Some patients have partial nerve dysfunction affecting the lower body (neuropathic POTS), which reduces vascular tone and venous return when upright.
Hyperadrenergic Response

Others experience excess release of norepinephrine upon standing, causing an elevated heart rate and sometimes elevated blood pressure.
Hypovolemia (Low Blood Volume)

Many patients have a reduced overall blood volume, which contributes to tachycardia upon standing.
Autoimmune Associations

Research suggests POTS may sometimes follow infections or immune-triggering events, and some patients show autoimmune markers, though this remains an area of ongoing study.
Triggers or Precipitating Events

POTS can follow viral illnesses, surgery, pregnancy, injury, or significant physical stress. Symptoms often begin after a physiological “trigger.”

Postural Orthostatic Tachycardia Syndrome (POTS) Symptoms

Lightheadedness, Dizziness, or Fainting

Occurs due to reduced blood return to the brain during upright posture, typically without a drop in blood pressure.
Rapid Heart Rate or Palpitations

A heart rate that rises significantly upon standing is the hallmark symptom of POTS.
Fatigue
Profound and persistent fatigue is a hallmark symptom of POTS, often disproportionate to an individual's level of physical activity. This fatigue can significantly affect daily functioning.
Cognitive Dysfunction
Many individuals with POTS report cognitive difficulties, including brain fog, difficulty concentrating, and memory problems.
Gastrointestinal Distress
Symptoms such as nausea, abdominal pain, bloating, and diarrhea can be troublesome for those with POTS.
Respiratory Issues
Shortness of breath and occasional chest pain may occur, particularly during upright posture.
Mental Health Symptoms
Anxiety, tremors, and sleep disturbances are common in individuals with POTS. The chronic nature of the condition, along with its unpredictable symptoms, can contribute to anxiety and emotional distress.
Thermal Regulation Issues
POTS can disrupt the body's ability to regulate temperature, leading to heat and cold intolerance. Excessive sweating may also be observed.

Testing & Diagnosis for Postural Orthostatic Tachycardia Syndrome (POTS)

Postural orthostatic tachycardia syndrome (POTS) shares symptoms with other medical conditions, such as dehydration, anemia, heart conditions, and anxiety disorders. Since POTS symptoms can be similar to other conditions, a full evaluation is needed to confirm a diagnosis. Some of the key tests used include:

Tilt Table Test
This is a specialized diagnostic test used to confirm POTS. During this test, you will be securely strapped to a table that can be tilted to various angles. Your heart rate and blood pressure are monitored continuously as you change positions from lying down to an upright tilt. An abnormal increase in heart rate upon standing is a defining characteristic of POTS.

Active Stand Test
This is similar to a tilt table test but simpler. You sit down for 5-10 minutes, then stand up unaided for 10 minutes while your heart rate and blood pressure are checked multiple times.

Physical Exam
Your doctor will listen to your heart, check your blood pressure lying down and standing, assess reflexes, muscle strength, and coordination.
Blood Tests
These help rule out other causes like anemia or thyroid disorders. Common blood tests include complete blood count, metabolic panel, erythrocyte sedimentation rate, and thyroid levels.

Autonomic Reflex Screening
This assesses how your involuntary nervous system responds to certain stimuli like breathing exercises or the Valsalva maneuver. Abnormal responses may indicate dysautonomia.