For people suffering from Orthostatic Intolerance, Postural Orthostatic Tachycardia, Mast Cell Activtation or EDS. Follow me as I document my struggle towards better health.

Mast Cell Disorders and POTS - Part II

If you have been diagnosed with Postural Orthostatic Tachycardia and/or Orthostatic Intolerance have you ever noticed that your digestive system can get uncomfortable and your body just doesn't like certain foods?  Have you been diagnosed with IBS or do you suspect you have Celiac Disease?  Do you feel better when you eat very simple foods such as proteins and veggies?  Are you sensitive to scents and perfumes? Do you react poorly when taking certain medications?

If you answered yes to any of these questions then investigating whether you have a mast cell disorder may be warranted.

What are mast cells?
According to Theo Theoharides from the Tufts School of Medicine:
Mast cells derive from the bone marrow and migrate into connective and mucosal tissues (Galli, 1993), where they are located at strategic points around capillaries close to nerve endings (Theoharides, 1996). Mast cells are critical for allergic reactions where the stimulus is immunoglobulin E (IgE) and specific antigen; however, there are also other nonimmune mast cell triggers that include anaphylatoxins, kinins, cytokines, as well as various neuropeptides (Baxter & Adamik, 1978; Coffey, 1973) such as somatostatin (Theoharides & Douglas, 1978), neurotensin (NT) (Carraway et al., 1982) and substance P (SP) (Fewtrell et al., 1982). When stimulated, mast cells synthesize and secrete numerous vasoactive, nociceptive and inflammatory mediators (Galli, 1993) that include histamine, kinins, prostaglandins, leukotrienes, cytokines, as well as the proteolytic enzymes chymase and tryptase (Schwartz, 1987). 
Mast cell disorders are still rather poorly understood.  As an Immunologist from Brigham & Women's said, "Our current level understanding of mast cells is similar to how well we understood T-cells in AIDS twenty years ago.  However, there is more research being done now which is very helpful in increasing our knowledge ."

How to find out if you have a Mast Cell Disorder?
The "gold standard" of diagnosing mast cell conditions used to be a serum tryptase test.  This is a blood test that can be requested by your family doctor.  Not many labs actually do tryptase tests so your blood sample could be sent as far away as the Mayo Clinic for investigation.  Tryptase is an enzyme which is produced by mast cells when they degranulate along with histamine and other substances.  An elevated tryptase result could indicate that your mast cells are busy and active.

However, researchers and specialists in mast cells now know a normal tryptase test does NOT rule out a problem with your mast cells.  Here is a link to a article published in the Journal of Hemotology by Molderings, Brettner et al in March of 2011 which not only describes the variety of mast cell misbehaviour but also diagnostic criteria and treatment options.

Does that mean I don't have to exercise anymore if my POTS or OI is related to a mast cell problem?
Whether your POTS is caused by mast cell problems or the cycle of the moon, evidence suggests that maintaining adequate blood volume and increasing your cardiovascular health through a specific program like the Levine protocol will help ameliorate the symptoms of POTS.

Unless you doctor specifically recommends you do not exercise because of some other reason other than you suffer from POTS or OI then you should really consider contacting the Levine team to see if you are eligible to participate in their study (I believe they are still accepting patients).


  1. So what are you doing differently now?

  2. I'm enjoying reading this blog - very informative, a wonderful, thought-provoking read!

    I find myself wondering/taking note of similar things, but just don't have the skills to write it all down in a linear way, that would be at all helpful.

    It has been a while since you have written a blog entry. It would be great to know how you are doing nowadays. Take good care.

  3. What evidence suggests that exercise improves pots? One study on a small cohort with low cardiac size?

    1. The original study has been expanded to hundreds of patients in multiple countries with, I understand, very similar results. I know for myself if I become deconditioned I feel much, much worse.

  4. Did I miss something? They jump from "evidence of normal tryptase dpes not rule out mast cell disorder" to talking about exercise. So how DO you get tested for mast cell disorder?