Why is it that after a two weeks of researching heart rate calculations I find the following information?
I have no idea, but I found this buried in the active.com website, it was on the wiki page for heart rates, and it seems to make complete sense to me. May be I like it because it seems to correlate with my own results, and that shows a bias on my part, but I’m going to document it here for completeness sake.
As I’ve been running I found that my HR zones seem to be calculated too low for the effort I was putting in while running. For example, to keep within the 80% range while running was really difficult as it felt too slow. Putting in sufficient effort to run the pace I require was jumping my HR out of the zone I was supposed to be training in.
Well, it seems like the reason may be that you shouldn’t calculate your zones as percentages of your Maximum Heart Rate (HRMax) but it should be calculated from your Heart Rate Reserve (HRR).
Your HRR is derived by subtracting your resting heart rate from your HRMax. You then use this to calculate the percentages for your zones and add it onto the Resting Heart Rate.
It sounds complicated but here’s a worked example:
My measured HRMax is 189 beats per minute (bpm).
My Resting Heart Rate is 61 bpm.
Therefore, my Heart Rate Reserve is 189-61=128 bpm.
The Heart Rate Reserve is essentially the amount of variation in beats per minute that my heart can support from resting to all out effort. It is this range that should be used for calculating the HR zone in which to train.
If we then calculate 1% of this value (1.28 bpm) we can use this to work out what the HR training zones should be.
My 80% zone would be at (1% HRR * 80) + Resting Heart Rate:
(1.28 * 80) + 61 = 102.4 + 61 = 163.4 bpm.
I know what you are thinking: surely a small change like this does make much difference to the end value? Well, if you compare my 80% value calculated from my HRMax (151 bpm) with this new value of 163.4 bpm, you can see that it is 12.4 bpm different. This is about a 10% off which is equivalent to an entire HR zone range!
Isn’t that fascinating? Why isn’t this info discussed on more pages? Or did I just miss it until now? The wiki page about heart rates says that there wasn’t much research into this but that it was used by Karvonen in a small study.
I will update my HR Calculations page to have this info in the chart.
As for a training update, I didn’t run today as I had a long, tough day at work yesterday topped off with a disturbed night from my daughter, but yesterday’s run was much more aligned with these zones of effort and actually leads me to believe that I could potentially get the speed I need in the appropriate HR zone.
At any rate (excuse the pun) I am looking forward to experimenting and finding out!