Training Zone Boundaries

[McFly]

I got to wondering…We often define zones by watts or by HR, and HR is the lagging indicator. When does a certain energy system “start” getting utilized/trained? Is it when the watts measure in the zone? The HR? Somewhere in-between?

For example, one of the training adaptations for Threshold is lactate clearing, but that wouldn’t start right away the moment the power meter read you were in that zone. And it has probably already been happening by the time you are breathing forcefully and HR is in zone.

When I’ve been doing my anaerobic intervals, I’ve always waited until my HR was at the higher end of tempo to start my timer, thinking I’m measuring better the time in the zone than if I start the interval timer when my HR may be as low as zone 1 at the end of the recovery interval.

[oldandfast]

There’s no spoon.

[Theyellowcarguy]

The typical coggan zones are really just approximate lines drawn in the sand. LT1 and LT2 are a bit more defined since you can see the lactate jumps if you monitor it closely. But mostly it’s just about the fatigue:reward ratio. If you increase intensity you can’t maintain the intensity as long which could potentially limit gains. Additionally it will take longer to recover from so could hinder overall training volume. Of course, you need some intensity so you have to balance it all which is where all the lines in the sand and coaching theories come from in order to try to find the ideal balance for each athlete.

[rswagler1]

If only we had Andy Coggan still on the forum… Trying to understand Sweet Spot - #115 by The_Cog
The power levels are really just a communications tool for coaches to use in describing workouts to athletes. The adaptations from exercise are on a continuum and occur across the spectrum, just in different types and amounts given the intensity.

[eddiegrinwald]

There can be benefits to both depending on where you’re working in relation to your FTP.

Generally speaking, I’d say that power is probably the better option in terms of defining training zones.

If you want to look specifically at effort, HR can be a good measure though.

Ultimately, unless you’re regularly lab testing fat/carb oxidation and lactate alongside your power/HR on the bike, these are only going to be estimations that won’t always be 100% accurate but are good enough for most of our training purposes.

The goal when setting these zones is to find your lactate threshold (it’s the easiest to estimate) and then base all of your zones (HR and power) on that one figure using a standardized formula. This means that your zones (again, both HR and power) might not always align 100% with reality.

For instance, your LT1 might be at a different percentage of your LT2 than mine, but we’re still using the same formula to calculate our zones. This means that your LT1 might be at the high end of zone 2 or maybe even the very bottom of zone 3 whereas mine might be at the middle of zone 2. Again, without lab testing it’s impossible to know.

Something I’ve done in the past is try to keep an updated and accurate FTP and lactate threshold HR so that I can look at those two data points together after my workouts. If I find that during certain efforts my zones are slightly off, I could probably assume that a good target for training purposes would be right in the middle of the two. From there I use power data since it’s the most stable, and consistent.

Your example of lactate/threshold training applies here. If your HR is in the threshold zone way before your power gets there, there is likely an issue with either your HR zone calculations or your FTP. Comparing these two data points helps in those situations. You should feel somewhat on your limit when riding at your FTP for longer durations of time. Sweet Spot is also hard, and it can be tricky to differentiate them sometimes, which is normal, but your HR should be relatively steady during both types of efforts.

Regarding higher power zones, I’d also recommend utilizing power data as HR lags far too much and isn’t always as steady during these harder efforts (it tends to drift upwards throughout the effort). In those cases, start your interval when your power is where it needs to be. Your HR will catch up and the effort is what matters in those cases, not your body’s response quite as much.

How are you calculating your HR zones? A common way that people do this is by using max HR figures which are actually really hard to accurately obtain and the formula is not super accurate in my opinion. I’d recommend doing a LTHR test if you haven’t to find and calculate your zones. It’s been more accurate for me at least.

Let me know if this helps!

[McFly]

That helps. Thanks!

I set my zones based on Friel’s percentages of LTHR, which I am estimating by feel. Above that is where forceful breathing becomes gasping, where good hard effort becomes very uncomfortable, where I’m watching the stopwatch for the end of the interval. I’ve not had a power meter on a trainer or my bike, so I’m doing it by HR and feel. I have race data to compare to, but my XCO races are nothing like a road TT, so my average race HR for 60-90 min may be higher than I could do steady state for that duration.

I agree max HR is not a good basis for zones, being of the opinion that whatever my recorded max HR is just means that’s the highest I’ve seen under those circumstances. I haven’t been chased by a bear or been given an adrenaline shot directly into my heart, so who knows what my hypothetical max is or what relation that is to my training zones.

So for those above-LTHR intervals, I may be starting with HR in zone 1 from the recovery time, so rather than start a 3min interval there I’ll increase my pace to get my HR in high tempo over about a minute. Then I’ll start the timer and up the effort again. HR will steadily rise to above LTHR before the end of 3 min, unless I’ve under estimated my effort or I’m spent and should call it a day. If I over estimate my effort, that 3 min interval might become a 2 min interval.

I guess it’s about time for a PM.

[eddiegrinwald]

Hey,

Thanks for that extra info!

I’d say that when forceful breathing becomes gasping you’re probably in that VO2 Max or above range.

For those above LT2 intervals, I’d still recommend starting the interval when the work begins, not when your HR has started to chime in.

Yes, a power meter is a great tool, but it’s not 100% necessary depending on your goals. If you really want to do structured training or use TrainerRoad at some point, you’ll need some way to record power data.

[MikeMunson]

Yeah, if you’re doing 3 min VO2max workouts, don’t wait on your HR. For 3 min intervals, it takes several intervals before my HR even gets to/above threshold HR, while I’m 115%+ above FTP.

I’ve been using HR for about 9 years (and started using power a few years ago, but inside only). You should do the Friel 20min test to get your LTHR (and do it periodically until you get it dialed in). Bear in mind, when/if you do start using power, that the lower Friel HR zones (% of LTHR) don’t match up with the lower Coggan power zones, so I had to switch my HR zones to Coggan’s so I wouldn’t lose my mind.

You should check out the TR thread about how to do VO2max workouts. The method many tout doesn’t require you to try to hit/hold a power or HR number (though I usually start with getting up to a wattage I know I can hold for the prescribed interval and go from there, based on how I feel). Kurt’s posts lay it out pretty well, though it seems some may be missing now.
Here: What would a custom VO2 max progression look like? - Training - TrainerRoad

[hubcyclist]

@MikeMunson

The method many tout doesn’t require you to try to hit/hold a power or HR number (though I usually start with getting up to a wattage I know I can hold for the prescribed interval and go from there, based on how I feel).

it’s how I do it, I have an idea of what power I want to roughly pace for the effort, but I also try to go higher than that. I like to say it’s an all-out but paced effort, which seems slightly contradictory at face value. This is a recent workout where I always try to set a PR on the first effort and hope to get as close on subsequent efforts (of course, I fail but they’re all max efforts). And as evidenced by the percentage of FTP across the efforts, it highlights the pitfalls of doing these TR workouts with rigidly defined workout targets

[DamonM]

I personally find the calculation for HR zones based on LTHR with Coggan estimates my zone 2 too low compared to Friel’s calculation. Not sure why there is such a difference but Friel feels more accurate when I am riding in power-based zone 2 and where my HR average ends up. The top of Coggan zone 2 HR I feel is right in the center of my actual zone 2 HR based on feel and being able to have a conversation with others.

[MikeMunson]

Yes, using a percentage of LTHR is an estimate for the zone breakpoints. And the LT1 point can change with fitness. I should have said that.

Heck, breathing and talking tests would lead me to believe my top of z2 HR is much higher when riding outside, but part of that making sense could be because I was using the Friel zones for so long. So, based on HR, I’m more likely to do 2 and 3+ hour oiutside rides in Coggan zone 3. But, inside, 225w is right at 131 bpm and I definitely wouldn’t want z2 to be any higher than that.