POTS is diagnosed only when orthostatic hypotension is ruled out and when there is no acute dehydration or blood loss. Orthostatic hypotension is a form of low blood pressure: 20mm Hg drop in systolic or a 10mm Hg drop in diastolic blood pressure in the first three minutes of standing upright.

  • POTS is a common condition affecting an estimated one to three million Americans.
  • The symptoms of POTS include but are not limited to lightheadedness (occasionally with fainting), difficulty thinking and concentrating (brain fog), fatigue, intolerance of exercise, headache, blurry vision, palpitations, tremor and nausea.
  • Researchers don’t fully understand the causes of POTS, but it is more common in women than men and is more likely to develop in adolescents and young adults.
  • POTS is diagnosed using either a 10-minute standing test or a head-up tilt table test; occasionally other tests are performed to identify specific characteristics of POTS present in some patients.
  • Most people’s POTS symptoms respond to a combination of diet, medications, physical therapy and other treatments.

POTS is a form of dysautonomia — a disorder of the autonomic nervous system. This branch of the nervous system regulates functions we don’t consciously control, such as heart rate, blood pressure, sweating and body temperature. The key characteristics of POTS are the specific symptoms and the exaggerated increase in heart rate while standing.

 

  • Postural: related to the position of your body

  • Orthostatic: related to standing upright

  • Tachycardia: increased heart rate

  • Syndrome: a group of symptoms

 

In most patients with POTS, the structure of the heart itself is normal. POTS symptoms arise from a combination of the following:

  • Lower amount of blood in the circulation

  • Excessive pooling of blood below the level of the heart when upright

  • Elevated levels of certain hormones such as epinephrine (also known as adrenaline since it is released by the adrenal glands) and norepinephrine (mainly released by nerves).

When we stand, gravity pulls more blood into the lower half of the body. In a healthy person, to ensure that a sufficient amount of blood reaches the brain, the body activates several nervous system responses. One such response is releasing hormones that help tighten blood vessels and cause a modest increase in heart rate. This leads to better blood flow to the heart and brain. Once the brain is receiving enough blood and oxygen, these nervous system responses settle back to normal.

In people with POTS, for unclear reasons that may differ from person to person, the blood vessels don’t respond efficiently to the signal to tighten. As a result, the longer you are upright, the more blood pools in the lower half of your body. This leads to not enough blood returning to the brain, which can be felt as lightheadedness (faintness), brain fog and fatigue. As the nervous system continues to release epinephrine and norepinephrine to tighten the blood vessels, the heart rate increases further. This may cause shakiness, forceful or skipped heartbeats, and chest pain.

 

Types and Causes of POTS

The causes of POTS vary from person to person. Researchers don’t entirely understand the origins of this disorder. The classification of POTS is the subject of discussion, but most authorities recognize different characteristics in POTS, which occur in some patients more than others. Importantly, these characteristics are not mutually exclusive; person with POTS may experience more than of these at the same time:

POTS symptoms vary from person to person and may include:

  • Severe and/or long-lasting fatigue

  • Lightheadedness with prolonged sitting or standing that can lead to fainting

  • Brain fog: trouble focusing, remembering or paying attention

  • Forceful heartbeats or heart palpitations

  • Nausea and vomiting

  • Headaches

  • Excessive sweating

  • Shakiness

  • Intolerance of exercise or a prolonged worsening of general symptoms after increased activity

  • A pale face and purple discoloration of the hands and feet if the limbs are lower than the level of the heart

POTS symptoms typically get worse:

  • In warm environments, such as a hot bath or shower, a hot room or on a hot day

  • In situations involving a lot of standing

  • If fluid and salt intake have not been adequate, such as after skipping a meal

POTS symptoms may also get worse when you get a common cold or an infection. 

Although the origin of POTS symptoms is physical, sometimes people attribute the symptoms incorrectly to psychological disorders such as anxiety. While some people with POTS have anxiety disorders similar to the general population, POTS is not caused by anxiety.

While POTS can be life-changing, it is not life-threatening. One of the biggest risks for people with POTS is falls due to fainting. Not everyone who has POTS faints. And, for those who do, it may be a rare event. But, if you don’t know that you have POTS, you may not take precautions against trauma from falls.

POTS can run in families, but no single gene associated with the majority of cases of POTS has been identified. A mutation in the norepinephrine transporter gene appears to affect only a tiny portion of POTS patients. Among genetic factors, there is a strong association between POTS and various joint hypermobility disorders, including Ehlers-Danlos syndrome. Recent research has also highlighted an overlap between POTS, joint hypermobility and mast cell disorders, some of which have a genetic origin.

POTS diagnosis can be complicated because the symptoms can affect a wide range of organ systems, and the most bothersome symptom for each patient may differ. In most instances, symptoms have been present for months before the diagnosis is made. Your doctor will perform a physical exam, order bloodwork and arrange a standing test or a head-up tilt table test to confirm POTS.

 

One may have POTS if all three of these criteria are met

  •  body produces an abnormal heart rate response to being upright

  • symptoms worsen when upright

  • orthostatic tachycardia in the absence of orthostatic hypotension

 

 

 

Another condition similar to POTS is inappropriate sinus tachycardia, in which the resting heart rate is usually above 100 beats per minute. Fibromyalgia patients, those with gastrointestinal motility disorders (such as irritable bowel syndrome), excessive sweating (hyperhidrosis) and many other conditions can also develop POTS.

Treatment for POTS should be tailored to each individual, because the symptoms and underlying conditions may vary widely. Although there is no known cure for POTS, the condition can be managed in most patients with diet, exercise and medications.