Fatigue and reduced exercise tolerance are prominent symptoms of both conditions, and dysautonomia may underlie both conditions.POTS can sometimes be a paraneoplastic syndrome associated with cancer.There are case reports of people developing POTS and other forms of dysautonomia post-COVID. There is no good large-scale empirical evidence yet to prove a connection, so for now the evidence is preliminary. Diagnosis
POTS is most commonly diagnosed by a cardiologist (41%), cardiac electrophysiologist (15%), or Neurologist (19%). The average number of physicians seen before receiving diagnosis is seven, and the average delay before diagnosis is 4.7 years. Diagnostic criteria
A POTS diagnosis requires the following characteristics:
For patients age 20 or older, increase in heart rate ≥30 bpm within ten minutes of upright posture (tilt table test or standing) from a supine position
For patients age 12–19, heart rate increase must be >40 bpm
Associated with related symptoms that are worse with upright posture and that improve with recumbence
Chronic symptoms that have lasted for longer than six months
In the absence of other disorders, medications, or functional states that are known to predispose to orthostatic tachycardia

Orthostatic intolerance
An increase in heart rate upon moving to an upright posture is known as orthostatic (upright) tachycardia (fast heart rate). It occurs without any coinciding drop in blood pressure, as that would indicate orthostatic hypotension. Certain medications to treat POTS may cause orthostatic hypotension. It is accompanied by other features of orthostatic intolerance—symptoms that develop in an upright position and are relieved by reclining.
Other conditions which can cause similar symptoms, such as dehydration, orthostatic hypotension, heart problems, adrenal insufficiency, epilepsy, and Parkinsons disease, must not be present.Treatment may include avoiding factors that bring on symptoms, increasing dietary salt and water, small and frequent meals, avoidance of immobilization, wearing compression stockings, and taking medications. Medications used may include beta blockers, pyridostigmine, midodrine or fludrocortisone. More than 50% of patients whose condition was triggered by a viral infection get better within five years. About 80% of patients have symptomatic improvement with treatment, while 25 percent of patients are so disabled they are unable to work. Retrospective studies has shown that five years after diagnosis, 19% of patients had a full resolution of symptoms.It is estimated that 500,000 people in the United States have POTS. The average age for POTS onset is 20 years old, and it occurs about five times more frequently in females than in males. Signs and symptoms
In adults, the primary manifestation is an increase in heart rate of more than 30 beats per minute within ten minutes of standing up. The resulting heart rate is typically more than 120 beats per minute. For people between ages 12 and 19, the minimum increase for a POTS diagnosis is 40 beats per minute. POTS is often accompanied by common features of orthostatic intolerance—in which symptoms that develop while upright are relieved by reclining. These orthostatic symptoms include palpitations, light-headedness, chest discomfort, shortness of breath, nausea, weakness or "heaviness" in the lower legs, blurred vision, and cognitive difficulties.