Symptoms, Causes, Diagnosis, Treatment and Prevention

Postural orthostatic tachycardia syndrome, or POTS, is a condition in which your heart starts to race when you stand up. Specifically, adults with POTS will experience a heart rate that is faster by at least 30 beats per minute in the first 10 minutes after standing.

POTS is a problem of the autonomic nervous system's control of blood flow (or circulation). Normally, when you stand up, gravity pulls more blood into your lower body; but to make sure that enough blood is still flowing to the brain, the body releases the hormones epinephrine and norepinephrine, which help tighten the blood vessels and increase your heart rate.

In people with POTS, however, the blood vessels aren't always able to tighten adequately, which causes more blood to settle in the lower half the body and less blood to reach your brain. When this happens, the heart beats faster in an attempt to shuttle enough blood to the brain to prevent you from losing consciousness.

Signs and Symptoms of POTS
While the main symptom of POTS is an increased heart rate upon standing up, there are many other symptoms that have been linked to the condition, including:

Fainting
Light-headedness or dizziness
Brain fog
Fatigue or exhaustion
Blurry vision
Heart palpitations
Nausea
Headaches
Head and neck discomfort
Chest pain
Shortness of breath
Coldness or pain in the extremities
A decrease in blood plasma volume, due to blood pooling in the abdomen and legs

Some people with POTS can experience a drop in blood pressure (hypotension) after standing, whereas others can have an increase in blood pressure.

Causes and Risk Factors of POTS
Not much is known about what causes POTS. Episodes of the condition can occur after major life events such as pregnancies, major surgeries, trauma, or viral illnesses. POTS may also occur before menstruation. Other health problems that are linked to POTS include impaired nerve function, poor blood circulation, and blood pressure abnormalities. In some people, POTS may be influenced by genes. For example, variations in the genes NOS3 and ADRB2 may be linked to an increased risk of developing POTS.

How Is POTS Diagnosed?
A POTS diagnosis can be challenging because of the numerous symptoms involved and the fact that symptoms can differ for each patient.
In addition to a physical exam, POTS is diagnosed with electrocardiogram (ECG) monitoring and in some cases with a tilt table test. A person will lie flat on a table, which is then raised to an upright position. As you're lifted up, doctors will measure your heart rate and blood pressure.

Other tests for POTS include blood and urine tests (to detect what might be causing the condition), and the quantitative sudomotor axon reflex test (QSART), which measures how well certain nerves are responding. Sometimes, people with POTS can be misdiagnosed with anxiety. The orthostatic symptoms of POTS — light-headedness, dizziness, tremulousness, palpitation, chest pain, fatigue, nausea, headache, and shortness of breath — overlap with common symptoms of anxiety, according to a review of studies published in December 2018 in the journal Autonomic Neuroscience. Study authors note that it's important to consider that people with POTS may also have an anxiety disorder. But POTS is not caused by anxiety.

Prognosis of POTS
Many people with POTS have mild symptoms, and therefore the long-term outlook is good. Medication, along with dietary and exercise changes, can help ease the symptoms of POTS — improving a patient's condition and quality of life. With time, some people may no longer experience any symptoms.

But prognosis varies, and some people may have more severe symptoms, which can interfere with their daily lives and worsen over time.

Duration of POTS
For some people, the symptoms of POTS may diminish — or disappear altogether — over time. This doesn’t mean, though, that whatever is causing POTS is also gone. Sometimes the symptoms of POTS reappear unexpectedly.

Treatment and Medication Options for POTS
POTS can usually be treated by your primary care physician. More severe cases may need to be treated in part by a specialist, including a neurologist or cardiologist.

Medication Options
There's no one medication that can directly treat POTS. Rather, doctors will prescribe certain medications to treat symptoms. Some of these medications include:

Fludrocortisone, which helps the kidneys retain sodium
Beta-blockers, which can decrease the increase in heart rate
Midodrine, which causes the blood vessels to constrict
Pyridostigmine, which affects parasympathetic nervous system activity

Your doctor may also prescribe medical compression stockings, which help push the blood upward in your legs. Additionally, your doctor might suggest you buy an at-home blood pressure monitor so you can check your blood pressure and heart rate.

Alternative and Complementary Therapies
One way to treat POTS is by changing your diet. Experts recommend drinking about 2 to 2.5 litres of fluid each day and increasing your sodium intake.

This helps expand blood volume, which then helps keep blood flowing to the heart and brain. Your doctor may recommend you take salt tablets to increase your salt consumption.
Certain foods or drinks can make POTS symptoms worse. Alcohol tends to exacerbate symptoms. Caffeine can increase nervousness and light-headedness in some people, while helping to constrict blood vessels in other people. It's a good idea to work with your doctor to find the dietary modifications that may be right for you.

Exercise can sometimes exacerbate the symptoms of POTS, so you may need to work with a physical therapist to learn what types of physical activity you can do. If you have difficulty remaining standing, for instance, you may want to try a mode of exercise you can do in a horizontal or reclined position, such as rowing or swimming.

Prevention of POTS
If an underlying cause of POTS can be identified and treated or managed, you may be able to resolve symptoms of POTS.
And it may be possible to prevent episodes of POTS by wearing compression stockings, changing your diet, or taking certain medications.

Complications of POTS
People with POTS can be at risk for falls, especially from fainting. Others, who have a more severe form of the condition, can experience a diminished quality of life. But POTS is not a life-threatening condition.

Research and Statistics: How Many People Have POTS?
An estimated one to three million Americans have POTS, according to Dysautonomia International. About 1 in 100 teenagers may have POTS.
While people of all ages, sexes, or races can develop POTS, the condition is more common in young women — particularly those younger than 35 — than men. (For each man who has POTS, five women will have it.) The condition commonly occurs after pregnancy, surgery, trauma, and sepsis.

Related Conditions and Causes of POTS
POTS is one type of dysautonomia, a term that refers to multiple conditions that affect the nervous system, which regulates functions such as heart rate, blood pressure, digestion, body temperature, and more.

More than 70 million people have some type of dysautonomia, including POTS. Other forms of dysautonomia include neurocardiogenic syncope (NCS), or fainting spells. Another is inappropriate sinus tachycardia (IST), in which the heart beats unexpectedly quickly while a person is at rest or only slightly active.

According to Johns Hopkins Medicine, most adolescents and young adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have POTS or related forms of orthostatic intolerance.

And fibromyalgia patients, people with gastrointestinal motility disorders (such as irritable bowel syndrome), excessive sweating (hyperhidrosis), and a number of other conditions can also develop POTS.

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