missptm,

Thanks for your question. 

Thickness of heart muscle is called hypertrophy and most likely your doctor is describing left ventricular hypertrophy LVH).  This is usually a response to the heart working a bit harder than it should be.  This most commonly is caused by long standing high blood pressure.  Some athletes develop LVH as response to their athletic demands.  Function is not usually affected unless the hypertrophy is advanced.  This thickening may also be evident on an electrocardiogram.

I suggest you discuss this situation with your physician.  You may need tighter control of your blood pressure.  As part of his examination, he/she should check all your pulses to be sure there are no major blockages that could put extra strain on the heart. 

Best wishes.

Martin Cane, M.D.