Zone 2 Power vs Zone 2 HR (Should I increase power to move HR to Z2?)

I did look at other threads, but even with lots of reading I did not get a clear answer.

FTP 303. Resting heart rate 35-37, max ~175.

My Z2 endurance rides are mostly all in Z1 heart rate. For optimal adaptations for this zone, should I increase power of my endurance workouts to put myself in Z2 heart rate? Please see pics.

I wouldn’t overthink it @varmstrong AT will adapt workouts if it thinks you’re managing workouts to easy and at the same time AIFTPD will increase your FTP and future workouts may be in HR Z2. But HR is such a fickle thing and can’t be relied on as much as power to get a consistent wo level, and if you have the latter (power) it can largely be disregarded.

Try using Coggan HR zones for a different viewpoint.

Thanks. Unfortunately, even looking at Coggan zones I am not matched up well. I guess the question is: Is power more important to make OR heart rate?

The problem is these are all easy workouts. I don’t think AT will increase them because as of now they aren’t taking HR into account.

whichever one leads to sustainable progress and sufficient recovery for higher intensity work.

It and AI FTP D will still up things eventually regardless of HR which to most purposes is irrelevant when you’re training off power.

FWIW Coggan was reluctant to give HR zones, because they can be very individual.

I’m not addressing your optimization question, just noting that HR zones is an interesting rabbit hole.


I think so too. Meaning AT may not catch it and I could be spending my time more optimally if I raised the power?

Are you following TR road plans? There are threads discussing optimizing endurance training, however they generally focus on non-TR plans that prioritize endurance training over intervals.

This is one of several attempts I’ve made to summarize the different philosophies of optimizing endurance training:

Good read, thanks. What do you mean TR road plans? I’m on XC Marathon plan… if that’s what you mean.

I think the reading helped quite a bit. Really I could do better by figuring out my LT1 and LT2 and corresponding HRs. I think I can do tests fairly cheap in the area (Washington state). I did do a VO2 max test, if that can get me closer. She didn’t take me all the way to max HR and I’ve lost about 12 lbs since then.

New to TR. After a bad FTP Ramp test. I had more in me. I accepted the low FTP more to see how well AI FTP will work. I am finding the workout too easy. I have been bumping them up 5-10% depending on the type workout. I am seeing my PL jumping. I am thinking of just doing a new Ramp test to get a more accurate FTP.

I suggest either bump your FTP a bit and see how the workouts are going or retest to see if your FTP is too low. Also find when I rate the workouts at the end I am often picking moderate or sometimes hard. I have plenty of time before my event and also coming back from being sick so I am feeling stronger very quickly right now. This I know will change soon.

As for HR SS and endurance workouts my HR is lower mostly Z1 or Z2. I tend to skip Z3. If I increase the effort just a little I go straight to high Z4. Max HR is 188 on the bike, 192 running. Not bad for an old man, but HR is so different for everyone.

I have a ramp test scheduled for Monday (but I wont do it, yay AI FTP!). So we’ll see what my zones look like after that.

I pretty much rate all of my endurance workouts as easy, though if i schedule a long one for myself i may do a moderate depending on how I feel.

I guess my broad question is this: Are the adaptations we’re looking for when doing Z2 rides tied more to power output or heart rate? Or are they tied to neither of those things but instead tied to LT1 and LT2? What percentage should I try to maintain for long blocks of Z2 stuff? If its 75% ftp but Z1 heart rate, would I get more adaptation catalyst at higher heartrate and power?


I have very similar stats as you do on the heart rate side with zone 2 rides. I also had tried to find an answer to what to focus on. End result was I really didnt find a definitive answer and just focused on riding by power. I felt like I was just over thinking it.


I know I’m digging up an old thread here so forgive me but I have noticed this myself when riding at endurance pace. My zone 2 power is in zone 1 heartrate. If I go by heartrate I’m definitely not in zone 2 power. I find this thread(and attached video) helpful but also leaving me wonder why we obsess over all these numbers and percentages then.

By the way- living near the Adirondack mountains means riding by power strictly is just not fun whatsoever. So RPE is a welcome answer.

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My two cents;

Make your hard rides harder and your easier riders easier.

Best way I heard Z2 described (by pogacar’s coach); you should be able to carry a conversation the entire time but- if you were on the phone, they would be able to tell you were doing something (maybe just not what).

I used to do my outdoor Z2 rides to power but I’ve since switched to HR. For me that just means keeping it below 135. The switch came from when I was doing a 3-4 hour effort and I hit the mountains and the temp kicked from 65 to over 100. My heart rate went from 135 to 160. I stayed to power and my Hr was 150-160 for the last 90 min. This imo was a failed attempt at Z2.

TLDR; I use power for all training zones accept Z2. Then it’s HR.

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This makes sense. What did you use to determine your zones? My zone two starts around 132 which by then Im usually in more tempo-ish power.

On my scale that’s a pretty high Z2. My max HR is 193.

Z1 <113
Z2 114- 149
Z3 149-168
Z4 168-186
Z5 186+

Oh ok got ya. When you said “keeping it below 135” I thought that was the top end of your Z2. My max is 186. I think I had it set to figure out percentages based of lactate threshold but not sure how accurate it was. Changing it to percentage of max heartrate brings me down more which may be more in line with my power now.

Too many ways to figure out HR zones