Updated 3/26/2026

Everyone knows what it feels like to be tired at the end of a long day. But for some people, fatigue is far more severe — overwhelming, unpredictable and difficult to put into words. When exhaustion feels debilitating or seems to appear without warning, it may be more than everyday stress.

While fatigue can have many causes, one condition that is often overlooked or misdiagnosed is postural orthostatic tachycardia syndrome (POTS). Physical medicine specialist Christina Kokorelis, M.D., answers common questions about POTS and the profound fatigue that can accompany it.

When is fatigue considered extreme?

There is no single objective measure for fatigue — it varies from person to person. Most people, however, can recognize when their exhaustion goes beyond simply not getting enough sleep. Many people can recall the exact day their fatigue became overwhelming, suggesting that something more significant might be going on.

How would you describe fatigue associated with POTS?

Fatigue in POTS can manifest in different ways, but many people describe it as an all-consuming exhaustion. It can feel as though the body’s energy reserves are completely depleted — far worse than the fatigue experienced with a typical illness like the flu.

People with POTS may also experience difficulty concentrating or thinking clearly, often referred to as “brain fog.” Even simple daily tasks can feel physically demanding, as though they require the effort of running a marathon.

This fatigue can be unpredictable. It may occur daily, weekly or less frequently, and sometimes appears without warning — even shortly after waking up. For some people, it lasts for days at a time; for others, it comes and goes. Rest, sleep or caffeine often do little to relieve it.

What is POTS and why does it cause fatigue?

POTS refers to a group of symptoms caused by dysfunction of the autonomic nervous system — the part of the nervous system that regulates involuntary functions such as heart rate, blood pressure, sweating and blood circulation.

In people with POTS, blood tends to pool in the lower body when standing. The heart responds by beating faster in an attempt to maintain blood flow to the brain, but this compensation is often not enough. Although the exact cause of POTS is not fully understood, it is thought to involve impaired communication between the brain and the cardiovascular system.

The fatigue associated with POTS is largely physical, though the exact mechanisms remain unclear. It may result from reduced blood flow to the brain, increased cardiovascular strain or the body using up additional energy to maintain circulation.

What are other symptoms of POTS besides the extreme fatigue?

 Symptoms can vary widely among people, but may include:

• Dizziness when standing
• Lightheadedness or fainting
• Nausea or vomiting
• Brain fog or difficulty concentrating
• Muscle pain or cramping
• Headaches
• Excessive sweating
• Tremulousness or shakiness

Many people with POTS also experience heart palpitations, a sensation that the heart is racing, pounding or skipping beats.

Is POTS more common in certain people?

There are no clearly established risk factors for POTS, although it sometimes runs in families, suggesting a possible genetic component. Researchers have also observed a link between POTS and Ehlers-Danlos syndrome, a connective tissue disorder characterized by joint hypermobility.

A large proportion of people diagnosed with POTS are adolescents or young adult women. However, the condition can occur in people of any age or gender.

Is it possible that I have POTS and was incorrectly diagnosed?

Yes. Because the symptoms of POTS overlap with many other conditions — and because awareness of this disorder is still limited — misdiagnosis can happen. POTS is sometimes mistaken for conditions such as chronic fatigue syndrome, fibromyalgia, anxiety disorders, ADHD, irritable bowel syndrome or other chronic pain syndromes.

In some cases, people with POTS are told their symptoms are psychological. While stress and mental health conditions can certainly affect how people feel, POTS is a physiological disorder. If your symptoms are persistent and unexplained, seeking a second or even third opinion may be helpful.

How is a POTS diagnosis made?

Diagnosing disorders of the autonomic nervous system can be challenging. One of the most commonly used tests is the tilt table test, which evaluates how the heart rate and blood pressure respond to changes in posture.

During the test, a patient is secured to a table that moves from a horizontal position to an upright position. Heart rate and blood pressure are monitored as the body transitions from lying down to standing. Some people with POTS may experience symptoms or even faint during the test.

Although the test is straightforward, several factors can affect the results. This is why evaluation is best performed under the guidance of a clinician experienced in diagnosing and managing autonomic disorders.

Is POTS treatable?

Although there is currently no cure for POTS, many treatments can help manage symptoms.

One commonly recommended strategy is increasing fluid and salt intake, which can help expand blood volume and improve circulation.

Exercise is also an important component of treatment, although it may feel difficult at first. Carefully structured exercise programs — often beginning with low-intensity, recumbent activities such as rowing or cycling — can gradually improve circulation and conditioning. Exercise programs usually ramp up slowly as activity tolerance improves.

Treatment plans should always be tailored based on the person’s symptoms, underlying conditions and overall health. Because responses to treatment vary, it is important to work closely with a knowledgeable clinician before trying new therapies, especially those found online. What helps one person with POTS may not be appropriate for another.

Medically reviewed by Christina Kokorelis, M.D.