Timex HRM with zones calculated on MHR

I've got a nice new birthday present of a Timex HRM (T5D741)and after figuring out how it works I see that the zones 1-5 are calculated using my entered max HR (i.e 90% of 177), not my working HR - i.e. 90% of 136 + 42 (resting HR).

This means that for e.g. the 60%-70% (106 - 124)zone programmed in the HRM is quite different to the 60%-70% (124 - 137)zone based on my working HR, which is what I had expected on the HRM.

How should the zones be calculated ? MHR or WHR ?

Has anyone else come across this and what do you do ? There is a manual zone which can be set each time, but that seems a bit of a nuisance.


  • Capricorn-I use WHR 'cos I can run at 70% while I'd be walking if I used 70% of Max:

    70% WHR = 145
    70% MHR = 130

    Sorry I can't help you with the TIMEX though..I've got an old Polar which I have to set manually.
  • Thanks Myley - that's what I've realised. 60%-70% of WHR seems about the same as 70%-80% of MHR, so that's what I'm using now for long runs.
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