Calculating LT1 and LT2 approximately without a blood test?

I’m not sure about the low hanging fruit part. Endurance physiology studies have maybe dozens of participants and in the grand scheme of things, there’s a tiny amount of research that’s been done into any of this. I think we’ve just scratched the surface.

After 2 years of doing more endurance focused work I have a good graph from Intervals.icu on power-vs-HR at relatively the same FTP:

That is % threshold HR (LTHR).

Previous seasons I did not have good data between 90-150W. What’s somewhat interesting is its basically a straight-line below FTP, which is what I’ve seen in several studies on PubMed.

That graph does require some context, as it can reflect the type of intervals you do, if you do some z1 work, etc., etc.

The “benches” at 83% and 85% and 88% LTHR are interesting, however I’m not sure if they reflect the work I’m doing or have some basis in physiology. I will say that 83% is where I detect a small change in breathing, during warmups. And that 88% is an average HR that I can sustain on harder 6-7 hour efforts without feeling crushed for days.

3 Likes

Thanks for sharing, some comments:

It’s really a shame. You have been training for 7 years and can’t produce a chart with at least 2-3 different “seasons”.

That’s why I always advice ppl that if they are going for powermeter, always get dual side and a high quality one.

Too short and too early for effective detection

This type of chart is mostly (only?) useful for comparisons in my opinion. You need at least 2 curves.

I believe your “average” methodology is quite flawed, if I understood it correctly. Unless you have a ride with steady HR 88% of LTHR for 6-7 hours, I don’t think you can make the average claim.

Finally, it’s interesting that your curve doesn’t exhibit the chaotic behavior typically observed above 120% of FTP.

1 Like

I cut off the chart above the “chaotic behavior” which is primarily chaotic because of doing intervals, and above threshold its hard to hold long efforts before you hit a wall. Most of the efforts in that area of the chart are where I’m doing endurance at say 138bpm and then do some 350W intervals and the first set is skewed to a HR below LTHR. And then a set break to bring HR back down again. That chart requires some context. I haven’t recently done a bunch of 13x30/15 or similar where it might provide a little better data to remove the chaos.

FWIW I do have rides for 5-8 hours with fairly steady HR 88%.

This is really an interesting comment. I had many seasons without ‘long enough’ steady efforts below 150w and you immediately bring up shame and comparing different seasons.

What does comparing a shift have to do with estimating LT1 without a blood test? If the curve I posted above shifted to the right, how can you use that to estimate LT1?

Are you planning to share anything with this thread?

2 Likes

I assumed you weren’t able to compare seasons because quality of data. I guess I’m confused as to why you can’t use the compare chart as intended.

I think if LT1 is within the shifted section of the curve, you can demonstrate an improvement.

I started my cycling journey with RPE and HR, went on a power, lactate rabbit hole and came back to HR and RPE. Is good enough…for endurance stuff. I know what happy tempo feels and I like to keep most of my endurance rides a notch or two under that, with selected excursions above.

Xert TP and LTP are pretty good boundaries for training when hibernation comes, as for power based numbers.

60% of Karvonen Heart Rate Reserve is also pretty good for estimating LT1.

Heat is the most important variable for HR based training of endurance.

There’s an unhealthy obsession with “steady” efforts in my opinion. This is driven by the research side of thing that have a hard time modeling reality.

88% of Max or 88% of LTHR? I have to see to believe. So you can ride 8 hours with no downhill? Or is this an indoor ride?

Plenty of quality data in most regions of that chart. And so I can compare seasons, and have, and it does show improvements and regressions.

However I was interested in the context of this thread, to see if there was anything interesting to see regarding estimating LT1.

That’s all.

The graph and all my references are % LTHR. I live in the Central Valley of California. Theoretically I could ride several days with no real downhills. There is a time and place for steady efforts, my longer >4 hours rides are “relatively steady” because there are stops for water/toilet and short-ish downhills after long climbs. And responding to terrain.

Anyways, I’m bored with reading and editing a legal contract at work Here you go, a recent long effort at and around 88% LTHR:

and

Took an 8 minute break around 3.5 hours. Starting riding with a slow guy around 5.5 hours. Waited for him at the top of the last climb by riding back and forth. Waited for slow guy at a gas station around 7.5 hours. I could have kept going at around 88% LTHR the entire ride.

Go ahead and tell me about my unhealthy obsession with steady efforts or whatever else I’m doing wrong or misrepresenting or misinterpreting :rofl: I could really use a break from this legal contract, its making my eyes bug out :face_with_spiral_eyes:

I’ve been there. If that’s what you like and fits your performance needs, go for it. I did a block of that stuff and left me a bit flat for the punchy stuff. Prolly good for long bike packing adventures.

1 Like

I do plenty of punchy stuff. And one steady 2 hour Tuesday ride a week. The entire year has punchy stuff, week after week, unless I was sick and/or coming back from a long layoff. And then its only steady/easy for a week.

That ride I posted was a casual century during my peak allergy season. Just took it easy as I have bad allergies.

1 Like

ok here you go, at 88% LTHR which is the upper end of my endurance/zone2 riding as mentioned above:

Timeframe power at 88% LTHR Notes
2017 204W self-coached “go long” double century A event and TTE of 60+ minuites
2019 159W 2nd year of TR, injured April-August but clearly struggling
2022 209W 2nd year of coaching with endurance+stuff approach
last 6 weeks 227W starting 3rd year of coaching with endurance+stuff approach

Felt and easily noticed the recent fitness bump. FWIW turned sixty this year and seventh year road cycling. YMMV and all that. No year averaged more than 8 hours/week. Huge amount of intensity in late winter / early spring 2017, which led to some crash&burn weeks but I had the base fitness to pick myself back up and keep going. Last two years its been boring old endurance plus a lot of intensity stuff, consistency for the win.

Everybody is different. Focusing on metabolic fitness is working well for me.

1 Like
  • 2017 was 2nd year of self-coaching based on the Time-Crunched Cyclist book and CTS (Strava) plans
  • 2019 was 2nd year of TR
  • 2020 trying FasCat off-the-shelf plans, liked it so much I hired a coach in August 2020
  • August 2022 was end of 2nd year of Coach Isaiah, liked it so much I paid for another year (most likely my last year)

for comparison, showing the 2nd year of 3 different approaches. Running out the door for a ride, but I think 2 years ago I ended up around 190W at 88% LTHR and 260 FTP. Then bumped to 270W ftp in 2021, and last night in the heat I was pacing threshold at 285 for 8 minutes and that felt really good. FTP up again, but I don’t know have a better range to share, and at this point I don’t care as it doesn’t impact my current training.

2 Likes

Hello,
I am looking to see if there can be a general consensus of what may be an acceptable means to estimate your LT1 that will get you in the ballpark, 80% of the time.
I would like to avoid blood tests and to be frank, if I were to go down the rabbit hole of getting a Polar h10 and the HRV logger or fat maxxer apps, do the tests, I am not sure I would feel I came away with 100% reliable numbers or even be able to interpret the numbers I do get.
Instead, I am hoping to do a rough estimate and by doing training in this approximate range, over a season, get me 80-90% of the way there vs if I spent a lot of time and money trying to find out what my exact numbers are, which as I understand it will also be changing throughout the year as I get more Z2 fit, hopefully (my understanding is that as you get more fit, and at the extreme for professionals, your LT1 HR increases, so your LT1 becomes closer to your max HR, the power you can put out while staying in Z2/at or under LT1, also goes up?)
So, after skimming through the previous 860 posts, I have gleaned what some people have put as estimates of their zone 2 and I would like to ask the community if there is agreement that any of the below could be used as “good enough” estimates.

Before I list my estimates, my understanding under the ISM recommendation of more Z2 volume is to bring about metabolic improvements. As such, it is my understanding this training should be HR based vs power based. If this is true, I am going to ignore the guidelines for basing your LT1 level from a percentage of FTP as I understand that it is better to follow your HR as a guide and not power.
Along the same lines I am going to list the percentages of your LTHR vs your max HR. Ever since TR got rid of needing to do a ramp test, I don’t think I have really pushed to my max HR on the bike. However, I feel like I have a much better guess on what my LTHR is as I also get notifications of it from training peaks and intervals.icu once they detect a change from a recent ride.

So, my estimate from reading this thread is that your LT1 hear rate can be estimated to be:

  • 83% - 88% of your LTHR

To be safe and conservative and if you are newer to zone 2 training, perhaps start at the low side, 80-83% of your LTHR (i.e. to try and ensure you are under your current LT1).
Then, as you progress through the year, slowly work your zone 2 rides towards the upper end of the range.

Sound reasonable? Close enough?

1 Like

ISM would use lactate to come up with both Power zones and HR zones. Personally I use power and only look at HR if something isn’t going well. Some do the opposite.

FWIW I’ve received LTHR updates from TrainingPeaks since 2016, and on my Garmin 530 for 3+ years. The Garmin 530 gives a lot of estimates, averaging about once a week. Except when I’m fully detrained, the LTHR estimates from my Garmin are usually within 2bpm and are consistent with what I see after 10+ minutes riding at ftp (when doing threshold intervals). I would not rely on % LTHR as detraining will cause my Garmin to show a 4-6bpm drop which is gone with 3-4 weeks.

1 Like

Work within that range but don’t worry about “upper end” “lower end”. It’s not about progressing from a certain lower percentage of the range to a few weeks later a higher percentage. Eventually that would come with time but you don’t program it.

The progression is duration based. Get a certain number of mins in and then progress the total amount of time spent in the zone.

Surround it with basic endurance riding, which is more like 70-75% of LTHR

1 Like

Yes, that how i understand it. I’m just not sure above moving to the upper range. You just do more power at the same HR, but i never saw any evidence that your LT1 HR evolves.

Honestly I think people over complicate things a lot. To be fair though that’s a lot of fun.
Personally for z2/endurance stuff I would ride based on RPE.

I have experimented with lactate, checked out dfa alpha-1 using a polar h10, and monitored respiration rate. All of them get me in the ballpark but I have found it’s easiest to just ride at 3-4 maybe occasionally 5/10 RPE and monitor decoupling over time.

1 Like

Thank you all for your quick replies.
For those wanting to also monitor power, what I have gleaned from this thread is that, LT1, can be estimated at:

  • 68% - 75% of your FTP

Hope that helps.

Yes, but the power is what you want to improve with long z2, so it will be a moving target.

What are you doing to get estimates on your 530? I have a 1030 and have not received any LTHR estimates.

  • wear a chest strap that supports HRV (Garmin dual HTM)
  • power meter on bike
  • set 530 to auto calculate FTP
  • record all rides on 530

When the 530 provides an FTP estimate, it also provides LTHR estimate. On the same screen.

I’ll have to check my settings tomorrow. I record all my rides on either my fenix 6 or edge 1030. Maybe I should pick one and stick with it. I always wear a heart rate monitor and always record my power. :man_shrugging:

1 Like