Cellular Hypothyroid & mild adrenal insufficiency cause of POTS

[letsfigureoutpots]

In all my reading thus far, with all the myriad associative causes for secondary POTS, what I suspect they may all have in common is cellular hypothyroidism, mild adrenal insufficiency (affecting cellular uptake of things like T3)....
The many "causes" of pots can cause, for instance, cellular hypothyroidism, which isn't detected diagnostically by most doctors because of the tests they use.  So, for instance, thyroid testing should include, TSH, free T4, free T3, reverse T3, thyroid antibodies, and an ultrasound of the thyroid.  (http://nahypothyroidism.org/deiodinases/)
The best test for adrenal function, so you're not chasing your tail, is 4 to 6 24-hr saliva cortisol and DHEA and antibodies.
I've noticed that many of the drugs consistently used to treat POTS could be, in effect, indirectly treating mild adrenal insufficiency.  Many problems from low Ferritin (indirectly iron store) to diabetes to...causes cellular hypothyroidism...which may cause or contribute to POTS.  My point is research the best tests to truly identify conditions, before they are ruled out by inadequate testing.

[LivingInHope]

I have what I believe is the hyperadrenergic form of P.O.T.S..  My TSH, free T 3 and free T 4 have tested normal.  

I've had cortisol testing and a pituitary related test for cortisol, but not the tests you mentioned.

I have struggled off and on with iron deficiency and last time I had it, my red blood cells went low, but my hemoglobin and hematocrit were fine.

[Red_Star]

I've had cellular hypothyroidism for over 24 years.  My nose thickened due to severe myxedema with normal labs for pete's sake! I cannot pinch any skin between my fingers anywhere except the tops of my hands.  Myxedema occurs in NO other disease but hypothyroidism. I also have Hashimoto's thyroiditis. I developed severe bradypnea down to 6 breaths a minute with extreme shortness of breath.  My paperwork finally showed subclinical (mild to no symptoms) hypothyroidism. I assure you severe bradypnea is not a mild symptom!