The rest of this page goes deeper into what POTS is and why symptoms can look so different from one person to another.
What Is POTS?
Postural orthostatic tachycardia syndrome (POTS) is a form of dysautonomia. It involves an excessive heart rate increase after moving upright, along with ongoing symptoms of orthostatic intolerance. A medical evaluation considers heart rate, blood pressure, symptoms, history, and other possible causes.
POTS affects how the autonomic nervous system manages automatic functions such as heart rate, blood pressure, digestion, sweating, and temperature. The condition can affect daily activities even when routine testing looks normal.
Why Standing Can Be Difficult
When you stand, your body must quickly adjust heart rate, blood pressure, blood-vessel tone, and muscle activity to maintain circulation. In POTS, that adjustment can be less effective. Heart rate may rise substantially while symptoms such as lightheadedness, palpitations, weakness, brain fog, or nausea appear.
This is why positional orthostatic testing looks at several measures together. A heart-rate change alone does not explain every symptom or establish one specific mechanism.
Nervous System and Cardiovascular Regulation
The autonomic nervous system uses sympathetic and parasympathetic activity to help your body respond to position, movement, stress, meals, temperature, and exercise. These systems work with the cardiovascular system, brain, spinal cord, muscles, breathing, and balance systems.
Research sometimes discusses measures such as heart rate variability when studying autonomic function. This is general education and is not a clinic assessment or monitoring service.
Commonly Described Physiologic Patterns in POTS
Neuropathic features
May involve changes in small nerve fibers that help blood vessels respond when upright.
Hyperadrenergic features
May include increased norepinephrine with tremor, palpitations, or a blood-pressure rise in some patients.
Hypovolemic features
May involve lower blood volume and difficulty maintaining circulation while upright.
These patterns can overlap, and classification varies. They are interpreted with clinical history and appropriate medical evaluation.
Associated Conditions and Possible Contexts
POTS or related dysautonomia symptoms may appear after a viral illness, including COVID-19 and Long COVID, or after concussion, surgery, pregnancy, puberty, or prolonged inactivity. Some people also have migraine, joint hypermobility or Ehlers-Danlos syndrome, mast cell activation syndrome, autoimmune conditions, thyroid problems, vestibular symptoms, or cervical complaints. An association does not prove that one condition caused another, and medical evaluation may be appropriate.
Comorbidity Screening
We review the history for commonly associated conditions, including Ehlers-Danlos Syndrome or joint hypermobility, mast cell activation syndrome, autoimmune conditions, and thyroid dysfunction. When appropriate, we recommend medical evaluation or coordinate with other healthcare providers.