I live in the country too, but it also looks like the power traces are a bit smoother on strava than the TR data analysis screen.
No out on the highway. Stopped a couple times to pee lol.
Iām glad to have found this post and the article from Tom Bell. My zone 2 power and HR for cycling do not align very well, and I am pretty much always in the lower end of my zone 2 HR range even when riding at the upper end of my zone 2 power. To get into what many would consider mid to upper zone 2, say around 130bpm (my max HR is 188 and my resting HR is 39) I have to ride at zone 3 power. This feels like it defeats the object of easy endurance riding, and I canāt find anything definitive on this subject explaining whether I should ride by HR or power for Zone 2 rides.
I am quite the opposite. My max heart rate is around 186 BPM and my zone 2 power is 150-205 watts. My Zone 2 heart rate is 112 watts to 130 bpm.
At the bottom end of my Z2 power I can maintain 130 bpm, but around 185 watts (indoor with two fans and around 70 deg. F) Iāll be closer to 140-145 bpms.
As a former recreational runner, you can really only measure Z2 by heart rate since thereās no power meter, so it makes it relatively simples. Since I picked up cycling early this spring, Iāve largely been doing my Z2 rides at the bottom the endurance range (around 155-160 watts) so I am around max Z2 heart rate and min Z2 power.
The last few weeks I have somewhat started putting more emphasis on varying my Z2 power rides and setting heart rate aside. I may be higher in the range and closer to 145-150 bpm. I do polarized training so my rides are basically either Z2 power or Z5/Z6 power.
It seems to be a bit of a grey area that I havenāt found a solid answer in for cycling (Z2 HR vs Z2 Power)
So earlier this week I did an 80 minute ride on the trainer with a 60 minute segment targeting around 127 bpm (bang in the centre of my zone 2 HR according to Garmin) and youāll see from the segment below that some of this interval had me in zone 3 for some of it, and at the higher end of my zone 2. I havenāt tested to see how long I could sit at this wattage before my HR creeps up. For reference my threshold is 290w which puts me at 4.3w/kg. Iāve been training around 6 hours a week pretty consistently for a couple of years now.
I think perhaps Iād be better off just training by power and sitting at around 200-205 watts, with HR around 122-123 bpm.
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Yes I would like to do a test like that. Would you recommend testing that at the top end of Zone 2 or the middle of Zone 2? And seeing how long until HR is no longer steady and moves up?
Those tabs are interesting. You can see that my power zone straddles Z2 and Z3, whilst my HR zone is bang in the centre.
Like the other poster has said above, itās frustrating how there appears to not be a definitive answer to using power or HR for base endurance training.
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Neither: ride to RPE 
hides
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TrainerDayās HR+ mode is actually what Iāve been using! Itās a very good system, but does require you to have your HR zones dialled in I feel.
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Good question. While I canāt really say for identical rides, my Z2 has naturally increased since my FTP has increased from 222 last March to around 272 now. With this growth, Iād have to think that my performance at all levels is also increasing and Iām frequently hitting PRās for power numbers ranging from 5 seconds up to 1 hr.
Regardless, riding at the higher part of my Z2 power absolutely has me in Z3 heart rate pretty quickly.
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Many would be better off if they were able to listen to their body and dial this in!
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Thereās no reason to use decoupling as part of determining z2 range. It can be influenced by too many things, notably heat and hydration which can be heavily swayed indoors.
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100% correct. More people need to actually listen to what their body is telling them during workouts.
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Someone said Z2 is a zone that should change the most between different workouts.
And best way for me to find the correct level for it is rpe.
When youāre fatigued and hr is low you shouldnāt raise power to get to the right hr range.
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Yes, that should be your goal. You still can pace by heart rate, but then you have to be sure that Z2 power = this particular range of heart rate. Even though 129 bpm sounds quite low for the upper limit to Z2, if that puts you above Z2 power, lower that target.
The reason is that heart rate measures the average load on your cardiovascular system whereas power measures the load on your muscular and energy systems. By staying within Z2 power, you make sure that both systems stay within the endurance zone. Right now it seems your cardiovascular system is fitter than your leg muscles, so you should focus on those.
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And if the repeat instances are done under the same basic conditions (like trainer rides the same day/time each week with similar prep and fueling) it can be reasonable as an additional tool for evaluation. Iāve done this for ages via my long Sunday trainer rides and the results usual correlate with RPE and my general fitness trend.
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