Exclusion of a secondary systemic cause (eg, hyperthyroidism, pheochromocytoma, physical deconditioning)
Patients with POTS present with
palpitations, severe fatigue, exercise
intolerance, presyncope, tremor, bowel hypomotility, and dizziness or lightheadedness. A significant proportion of patients also complain that they always feel cold and are unable to tolerate extreme heat.