I’m close to the end of the second week (or first complete week I should say) of my new Polar half marathon running program. It was nice and fun, but the biggest challenge was the way Polar defines the default heart rate zones. Based on the maximal running test, my Max HR is 186bpm, which forces for example my HR Zone 2 to be 112-129 bpm. Staying under 130 bpm for me is a very difficult task as I’m struggling to find a way to run and not walk below 130 bpm.
With the hope that I’ll find out that the running test wasn’t relevant and I could gain some degree of freedom for Zone 2, I did another running test, a sub-maximal one … the result confirmed the initial findings, not affecting the max HR (as it wasn’t , but MAP/MAS and even VO2max being the same… saying kind of that the initial test still stands ..
Now … with the HR zones .. the default Polar ones look like this:
If you use the same Max HR of 186, a resting heart rate of 60 and use the Karvonen formula you may get a different set of zones:
To me, those Karvonen based zones look better and more “palatable”, especially Zone 2. Some may say that I’m inefficient aerobically and I should continue with the Zone 2 designed by Polar and train until I get accustomed with it …
Let’s add something more here … the power zones from Stryd (I wear Stryd because I trust more it’s measured distance and pace than what the GPS watches can provide, regardless of brand – be it Garmin or Polar).
Looking at my recent runs, I noticed that staying the Polar default HR Zone 2 makes me just enter the Stryd power Zone 1 – for example the warm-up in HR Zones 1-2 gives an average power of 188W, close to the lower limit of power zone 1.
With that in mind, I tried to understand where my HR would be if I still stay in power Zone 1, but don’t look too much on the HR, but just use the power zone lock of the Polar Vantage V2.
And the result seems to be confirming that Power Zone 1 (mid zone) is keeping me in the HR Zone 3 (default Polar) which is kind of crazy … I mean I understand that I’m not that fit, but still that didn’t happened in the past. Basically, looking at the zones based on Karvonen formula kind of match the Zone 1 Power – which is supposed to be easy. I’m very much tempted to adjust the HR zones in Polar Flow to the values derived from Karvonen formula and continue to use the program as it is … but still less painful to follow.
Polar mentions the Karvonen approach on their website here when discussing about heart rate zones, but “officially” they are still promoting the 50%-100% of Max HR split in 5 zones described here. Polar seems to be inclusive in their published materials, even the MAF method being mentioned here when designing the heart rate based training programs.
I’m a bit torn – I picked to use the Polar Vantage V2 for my “athletic rehabilitation” because I trusted more the heart rate knowledge they display and now I’m twisting the reality to fit my perceived HR load. Polar Flow doesn’t allow multiple ways of calculating the HR zones – it’s their way (based on Max HR) or your custom zones, which can be anything you want. So, I could easily adjust the values there, sport by sport, or at least running with the Karvonen results and keep on training using the current program.
With Garmin Connect, you have the freedom of choosing one of the three methods to determine your zones – max HR, heart rate reserve (Karvonen) and Lactate Threshold (LT) based zones.
Because Garmin has a Lactate Threshold guided test (and not only), they are favouring the LT based zones, but you could still use any of the solutions, including the % of Max HR.
Looking back in the year 2020 Garmin statistics, the Max HR average is 188 … which kind of makes sense and the average LT is 174.
There are many other options available to setup your training zones, for example the one mentioned often being MyProCoach which is pretty close to Karvonen in my case.
Things become even more complicated if you go to TrainingPeaks and try to adjust your zones there .. you have even more options to defined your zones, based on Max HR, Lactate Threshold, Resting Heart Rate.
For now, I’m trying to hold on to the Polar device and platform usage, even though the “advantage” of using the program and tools in their unaltered form failed, if I’ll switch to Karvonen edited HR zones that would be updated every time I’d do the maximal running test – which fortunately would happen only once every three months.
Since I don’t have a personal trainer, I love the support the devices and platforms offer you … Garmin for example collects a lot of data and with the help of the algorithms from FirstBeat they detect you LTHR even without you doing a specific test (it might not me as accurate as lab tests, but it’s there magically without the effort of doing something supplementary to your running session), Polar tries to do something kind of similar with the running test, adjusting your HR zones, MAS and MAP (unfortunately MAP is still calculated with Polar running power, regardless if you use the Stryd during the test).
Stay safe and run happy!