Power zones and HR zones mismatch


I’ve noticed that when I train based on power, my HR readings are always completely at odds to my power data. I’ve tried including a could of screenshots. My HR zones are pretty accurate as I’ve been training based on HR for a long time for running and I use a new garmin HR strap, so I think the data is good.

Can anyone explain this difference? And whether I should be training closer to my HR zones than my power zones.

Thanks in advance

Accurate for running. You need different zones for cycling and running.

Apologies, I should have been clearer. They are different for cycling and running. I just meant I’m not new to use HR data to plan training.

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How did you set them for cycling? And I assume you realize that zone alignment may not happen, and may not be a goal.

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Since you have power I’d ignore HR other than a curiosity as HR is such a fickle thing. If I look back in my records I’ll probably find rides when HR and Power closely aligns but on other rides they’ll be vastly different. There is an argument though if you are doing a Z2 type ride or below you should limit yourself by your Z2 HR (assuming your zones are set up correctly) and for workouts higher zoned than that use power.

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Thank you @HLaB and @WindWarrior. That’s helpful. The main reason I’d been looking at it is I don’t have a power meter on my bike, just my turbo trainer, so I have to use HR when I’m out on the road. Not ideal, but next step is probably to get a power meter for the bike so I can be consistent indoors and outdoors. Thank you again

I think TR recommend in that case outdoors you train off RPE https://support.trainerroad.com/hc/en-us/articles/360021324932-RPE-Key-Explained

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My heart rate isn’t fickle, if your isn’t then you could use TR workouts inside to customize your HR zones. I’ve always trained by HR, and then power. Both work great and deliver results :+1:


From my own experience, I also started training with HR before I had a power meter and an indoor trainer.

Do a dedicated HR test on the bike. For example with Joe Friels protocol - you could read more on TrainingPeaks about different methods Joe Friel's Blog: A Quick Guide to Setting Zones

Then you could check how the zones from the test align when you do indoor training at sweet spot, threshold, …
They may not align perfectly. For me it matched surprisingly pretty good and what I expected from pre-power meter.

Now you have some idea of how to use HR outside. Note you still have all the problems of HR training (other things than power output affect your HR - heat, bad night sleep, …)