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Myasthenia Gravis

Orthostatic intolerance



I have trouble standing or walking in warm stuffy places for any length of time. If I am forced to stand or walk in such an enviromnent, I get weak, "tired" feeling and I have no choice but to sit down. It`s not that I feel faint, but it feels like my body just can`t handle my standing any longer. I feel so very relieved when I do sit down during one of these episodes. It "feels" like a cardiovascular problem, almost like I have a bad autonomic system, but I`m not sure.

The other day this happened and when I sat down I counted my heart rate at 50 then, a few minutes later it went up to 80 and stayed around there.

I have previously been diagnosed with MG. Could this be related to MG or is it most likely something else?


Muscle weakness in MG can worsen in a hot humid environment. Also, pyridostigmine -- a medication taken for control of MG -- can slow your heart rate. I think it is worthwhile for you to see your MG neurologist again. S/He will be able to sort this out.

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Response by:

John G Quinlan, MD John G Quinlan, MD
Professor of Neurology
College of Medicine
University of Cincinnati