I’m trying to do zone 2 training as suggested by Iñigo San Millán.
The problem I’m facing is that I have two very different estimates of my Z2 heart rate, one from my Garmin and one from intervals.icu.
Though the number of zones in each is different, both have Thershold (and top of Z4) at ~163.
The issue is that they divide the space below that threshold value very differently.
Specifically, garmin has Z2 at 110-127 and intervals.icu at 132-145.
Why such a big difference, and which should I trust for Z2 training?
Some more context:
I use the default setup for both.
I pass “the talking test” easily on garmin’s Z2, it becomes much harder to talk at the top of intervals.icu’s Z2.
Garmin zones: Z1: 92-109, Z2: 110-127, Z3: 128-145, Z4: 146-164
Intervals zones: Z1: 0-131, Z2: 132-145, Z3: 146-152, Z4: 153-162
shouldn’t your zones be in sync or are you looking for guidance on which is the “correct” one which you should be following?
Note that the zones in (both) GC and Int.icu has some pre-determined numbers/pct%. These may not entirely be corrct for everyone. Your best bet is to “test”.
This podcast will answer your question on which Z2 to use is correct: “the average”.
Start just before 1:24:00, as this will lead into the discussion where they talk about the ordinary person knowing where Z2 is. Metrics for finding Zone 2 threshold—lactate, heart rate, and more [1:24:00]
They talk about the difference between measuring (lactate) vs RPE.
the links in the other thread are for FTP testing, but my question is regarding the apparently very different ways to extrapolate Z2 out of this number.
btw, the extrapolation formula used recommended by training peaks/Joe Friel is what I have set up in intervals.icu.
I was actually listening to this very podcast over the last couple of days and that’s what got me to try and sharpen my definition of Z2, which led me to realize there’s more than one way to extrapolate that from FTP, etc etc
I guess I’ll just try to aim a bit higher every workout, until I get to a point where I “fail the conversation test”.
I was hoping to gain some insight into the different extrapolation formulae that can be used, but I do realize that these will always be averaged out over the population, and I’ll need to find my own Z2 no matter which of them is “better”.
The YT video and the podcast (which I listen to) aren’t aligned on the same timeline.
1:25:03 ISM talks about fat oxidation being lower
1:13:01 ISM talks the same thing.
There are a few ways to approxiamate your upper limit of Z2.
RPE and talk test (which they describe).
Lactate test
Garmin AlphaHRV app (with a step test)
Generic zones set by apps
The next important thing to note is that you don’t have to work at the top of Z2, to get the same benefit. If you work below it (mid zone) you will still get the same benefits.
A safe starting point can be estimated by the MAF formula: 180 - age.
Use that for a week or 2 until you really recognize the feel and if it feels too low, add a couple beats until you notice a change in breathing effort. Then back off again. If you go more then 5 - 10 beats over the estimated value, you are almost surely too high.
yes, but the very top of garmin’s Z2 estimation is still in Z1 in Friel/intarvals’ estimation, and if that were the case the workout would in fact be less beneficial, not?
my plan now is to start gradually raising my target HR for Z2 workouts and use the conversation test to try and determine my Z2 limit. I’ll also try and do the step test with AlphaHRV when I get the chance (hopefully next week).
Perhaps, maybe, very slightly…
I know it goes beyond every athlete’s reasoning (‘no pain no gain’ thinking), but the impact of those couple beats is absolutely trivial when it comes to fitness effects. It is more likely to contribute to consistency if you go just that tiny bit slower.
You can change the zones to suit yourself, so that they all report the same across platforms. I use the Coggan zones in my setup, but my Z2 is lower than what the Coggan shows it should be. It doesn’t mean my fitness is poor, but rather that I won’t be in Z3 when a few beats above “my” zone 2. The Garmin AlphaHRV step test shows an LT1 which is close to what Coggan shows, as well as data I had checked by Steve Neal (another type of HR step test).
ISM agreed with Peter Attia, in the zone 2 discussion, that 70-80% of maxHR is a wide range for zone 2 upper limit; for me that would be a 21bpm difference. That’s why they said mid-range even when lactate might say one level, a calculation another and feel something else. Doing a lactate test is not absolute either, but rather just a snapshot on the day.
The more you ride (frequency), and “feel” when it starts becoming uncomfortable, the better you get at knowing what it should feel like. As @MedTechCD said, many people feel that too easy feels wrong, when easy is actually better. Compounding effect of multiple doses of easy work.
and that’s what got me to try and sharpen my definition of Z2, which led me to realize there’s more than one way to extrapolate that from FTP, etc etc