DigiFit) on my iPad. Twenty minutes into the exercise the bp crash occurred and I fell off the rowing machine. The same blood pressure crash occurred the following day and the day after that. The crash did not seem to occur when my heart rate increased rather it crashed after the increased heart rate was sustained for >5 minutes.This new symptom was perplexing because previous to then I had not had a blood pressure crash while sitting and exercising (rowing).
I emailed Dr. Levine's team describing these events. The response was as follows: 1) these events are not consistent with typical POTS, and 2) they are probably not due to a structural defect with the heart (I was thoroughly checked for this). Intriguingly I was asked if developed hives or shortness of breath while exercising. I didn't but the question led me to investigate exercise anaphylaxis.
Exercise Anaphylaxis: Def - A form of allergy manifest by a sensation of skin warmth, pruritis and erythema, urticaria, hypotension, upper airway obstruction DiffDx Cholinergic urticaria, anaphylaxis. Websters DictionaryWell, it just so happens that a group at Brigham & Women's Hospital is conducting a clinical study on exercise anaphylaxis. This group specializes in immunology, and more specifically, mast cell disorders. I called one of the researchers and gave her my abbreviated medical history (the long form of the history takes several hours) which she kindly listened to. She suggested that based on my history of POTS and anaphylaxis as a child I be investigated for a mast cell disorder.
Can mast cell disorders cause POTS? The answer to that question appears to be yes. In an article entitled Understanding the Mechanisms of Anaphylaxis by Richard D. Peavy and Dean D. Metcalfe from the Laboratory of Allergic Diseases, NIH they talk about when mast cells are activated producing histamine.
Histamine stimulates vasodilation, and increases vascular permeability, heart rate, cardiac contraction, and glandular secretion.Sudden vasodilation causes blood pressure to crash and people to fall off rowing machines. Mast cell disorders and POTS...a worthy line of investigation for someone looking to get at the root cause of their POTS!!