Racing with a HRM

I'm trying to find out whether anybody uses a heart rate monitor during races.

I've only done one 10k so far and used my HRM and the percentages as quoted in Parkers "HRM Training for the Compleat Idiot" as a guide.
He says:
75% for Marathon
80% Half-M
85% 10k
90% 5k

I ended up going too slow (I felt too comfortable at the end of the race) for me to believe that 85% was right.

Are the percentages right or should I just use the HRM for training and rely on pace rather than heart rate for racing?



  • This is a tricky one.

    Firstly, I would say that if you want to use an HRM for races its doubly important that you have an accurate idea of your max, otherwise, possibly the case here, you are in danger of running too slowly.

    Seondly, and this is a personal view, it depends where your lactate threshhold (LT) is. Running tempo sessions in training will help you find out (and improve) your LT but simply speaking if you try and race above your LT, whatever your heart rate might be telling you, then you will slow down.

    Thirdly, there is a concept known as "cardiac drift" which estimates that your HR will increase by about 5% (5-10 beats) during the course of a race (as you get tired) for no increase in speed. Thus whilst your percentages might be right for the start of a race, they are probably too low at the end i.e. at the end of a 10k you can expect to be closer to 95-100% of max.

    The final factor is more subjective and depends on your own motivation to push harder.

    Having said that I have started using an HRM during races this year and found it very helpful for not going off too fast but also even pacing (by building into my race plan an estimated increase throughout the race). Overall though I would say you are better off using a few races to simply gather data (i.e. run as you feel) or experiment e.g. why not try running the first half of a 10k according to your HR estimate, then run the second half without looking at the HRM but run as fast as you can then see what happens to your average in the second half of the race.
  • StinkyTrainers

    I always race by HRM but at a lot higher levels than you indicate, for example,

    Over a 10k road race I will do
    2k @ 88%MHR
    7k @ 92%MHR
    1k @ 94%MHR

    These HRs are based upon my LT of around 93-94%MHR – If you race a 10k hard, but at a steady pace, then look at your average heart rate this is a good indication of your LT

Sign In or Register to comment.