<There really may not be a problem.  I've always 
    been told to avoid the 200bpm range, especially on a youngster.  The 30 
    beat difference during most of the conditioning ride may be no big deal, 
    though, after several months of conditioning, I couldn't figure out why the 
    gap didn't narrow.  It could be they are just at opposite ends of 
    normal.  I can condition him easily, hills, extension, whatever and 
    never get near 200.  When I condition on hills, even moderate hills, 
    she goes over 200 and stays there to the top.  However, even when I 
    take her on a 3 mile hill with a good grade, she's at 210bpm the whole way, 
    she recovered to 60 in 3 1/2 minutes.  The gelding does the same hill 
    and never breaks above 170.  I do have a stethascope and have verified 
    the resting rates on occassion.  It could be that I need to stop 
    fixating on that 200bpm number.>
     
    Hi again Cathy,
    OK your latest message has clarified things a 
    bit for me.  I think why people have suggested you keep out of the 
    200bpm range is because to get within this range generally means some sort 
    of interval training, which isn't really appropriate at this stage in your 
    mare's development.
    If she goes into this range after no real 
    effort then possibly you have a problem insofar as she is technically 
    working anaerobically with the attendant lactic acid accumulation 
    problems.
    What does your own vet think?  Is it worth 
    doing an electrocardiogram to check that there are no abnormalities 
    there?
    I still think its not a good idea to compare 
    hr's between horses, I've seen such variation with my own horses, even 2 
    horses with the same level of experience & working towards the same 
    goal.
    If the hrm is working correctly & you say 
    you've verified with a stethoscope, then it would surely indicate some 
    sort of stress, generated by what is another question.
    Taking blood after a conditioning ride might be 
    a useful exercise to see what the effort provokes in the way of muscle 
    enzymes, etc.
    Does she show ANY kind of stress at all at 
    rides or at home?
    If she is hurting somewhere but is a generous 
    mare & wants to please it may just be her way of saying 
    "help".
    Good luck
    Heather