normal labs - still high heart rate

[cycle4ever]

I have posted before regarding recent diagnosis if hyperthyroid from Graves and high heart rate from excersise.  I am an amatuer cyclist and before the diagnosis and meds HR during racing would hit 195-205.  I have been on an anti thyroid for a couple months now as well as a beta blocker to keep HR under control during cycling.  I had a Dr appt last week and my lab results came back in the normal ranges.  Dont know what they were except that the doc took me off the beta blocker and reduced my methanizole ??? from 15mg to 10mg.  I have been riding now for a week without the assistance of the beta blockers and unfortunately my HR jumped back up to the 195-200 range.  Again excercise was very intense but other riders were maxed out at 175 - 180bpm.  Before the ride my HR was 102 while another rider was sitting there at 71bpm.  I called the doc back to see if I should still be on the beta blocker but was told to stay off of them but no answers were given about the HR issue.
Long story to ask if I should be concerned about the HR during excercise.  Do I need to have other tests done?  Will it just take time before HR recovers from the meds I am on?  EKG done several months ago before thyroid diagnosis and was told heart was strong and no issues.  However, I dont want to be causing any undo stress on my heart and create future problems.  

[Mark Lupo, M.D.]

I think giving it more time off the beta blockers is preferred.  The thyroid levels must have been normal or slightly low to decrease the tapazole, so usually we stop the beta blocker at this time for otherwise young healthy patients.