LTHR as high percentage of max HR

Hey everyone,

Just a quick poll for the group. Does anyone else have a calculated LTHR that seems like a pretty high percentage of their max heart rate?

At age 37 I have a max hr of 205 (saw this during an untrained charity 5k about six months ago), and the 4DP calculates my lactate threshold as 187.

This seems high. As a result traditional heart rate zones get super compressed at the top end. Like, people say a good indicator of reachin vo2max is that your heart rate hits 90% of max. This says LTHR is above that! So getting up to vo2max is super tough.

anybody else have this issue? and what’s the approach when it comes to trying to do intervals where you reach vo2max? If reaching vo2max means reaching 90% of max, then no problem, but if it means reaching LTHR plus some amount, then i’m going to have to work a lot harder and modify the SUF plans in order to do it: I’d have to make the MAP targets harder, and also rest more leading up to each interval session.

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I’m at ~90% of max for LTHR (that’s the very rarely ever seen unicorn max not typical workout max). If I ride at my “FTP” for a sustained period of time then my HR settles at LTHR. If I do a 1min-per-step ramp test (like Half Monty) then I’m well over “FTP” by the time my HR hits LTHR (and subsequently well over LTHR by the time I fail!). If I’m training VO2max then I’m going by RPE not HR (oh and power if I must) but do get in to that zone between LTHR and max.

Terminology is definitely a factor to consider when talking HR. There’s a SUF article on everything you ever wanted to know about HR but were afraid to ask…


yeah that’s what i mean about using heart rate for vo2max workouts. Not that you do the intervals at that heart rate–it wouldn’t work–but that i want to eventually get up into that range and spend as much time there as possible. In order for that to happen i need to go HARD.

But thanks, i’ll take a look at the article. Maybe the issue is that i sandbagged my 5 min in the 4DP and those power targets should be higher . . .

also i should further clarify, i hate calling these vo2max workouts because obviously there are many ways to increase vo2max besides the superhard intervals that people tend to call “vo2max intervals.” It’s a frustrating misnomer, i think.

So i should say, “max aerobic”, or “intervals where you achieve vo2max as a state” :slight_smile:

I’m on the same bus as far as VO2max is concerned. Especially this ‘max’ bit whatever that means.
Though I guess I do use VO2 sometimes myself to describe workouts right enough - they’re either tempo or around ftp or vo2.
I never think about it beyond that, as the workout is designed to achieve a goal, and if I’ve got my 4DP close enough, then (let’s use Nine Hammers) the workout will make my body do the right stuff - one of the reasons I like SUF - it’s clear what each workout does.

Actual numbers wise … apart from a recent 4DP (HR running high all the way through) my LTHR is typically between 92.6 and 94.3% of max. That’s max that I might see twice a year maybe. Which looks not dissimilar to your LT vs Max - a bit higher as a proportion in my case.

And as far as Nine Hammers is concerned I’d expect to be going going that LTHR during the harder intervals. I think that’s pretty normal. So yeah - ftp for me will broadly sit at LTHR and going any harder than ftp will bring hr above that. The further above the quicker that happens.

The 5 min test puts me squarely between LTHR and max.

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Based on recent HM my LTHR is 165 so 93% of max HR (178)

My HR at FTP is about 160 or 90%. This is also the value FF gave me. I know there is no way I could hold a HR of 165 for an hour.

I don’t use HR for MAP style intervals. I do however use it for longer intervals or segments.


Guys, thanks for sharing your thoughts. Sounds like my LTHR as a percentage of max is i guess high but not that high. I’ve held a high heart rate for an hour or hour and a half (180 and 179 respectively), but never LTHR of 187.

I guess i should clarify, i don’t really use HR for MAP intervals per se. But, i use achieving a certain heart rate as an indicator that i’m pushing hard enough to get some of the adaptations we’re after.

After all, there’s a lot of benefits of different intervals, MAP included. You’re stressing that glycolitic system, you’re increasing lactate usage for fuel / production of the transporters that bring lactate out of the fast twitch muscles, you’re increasing the tolerance for the acification that comes from those hydrogen ions that the lactate pulls out of the muscles etc.

And for some of these, maximizing time spent at vo2max is, IIRC, the best way of maximizing those adaptations. So i use whether i’ve hit the right HR # after the fact as a way of judging how “successful” the session has been in that respect. I’m not using it to guide the intervals, but at the end of the day, i’d like to have spent some time up there.

I agree that one of the best things about SUF is how the workouts are designed and how they are individualized–it’s the platform that probably has thebest level of individualization of all of them. But that said, I think it’s empowering to know how and why the workouts work, so that you can individualize even further.

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The LTHR calculated from Half Monty, is based on your peak 1 minute heart rate, not just the peak. Some folks hold their max heart rate for the final minute of the test, others only hold their max heart rate for a couple seconds be fore failure.
There are many variables that impact heart rate, and LTHR, and how those relate to one another. The current calculations are based on the population data sets we have, but we will be working towards updating the calculations to take more factors into account to improve the accuracy.
As far as using heart rate to gauge the VO2 training stress of a session, it can be an indicator, but many other factors have to be taken into account, like intensity and duration of efforts completed, recovery intensity and duration between intervals etc.
As a question for you, is hitting a 205 bpm heart rate normal for you to do on hard workouts? If your heart rate on the day was abnormally high, the would impact the estimated LTHR. For reference, if you look back at past FF tests, what was your peak 1 minute heart rate then?


Thanks, Mac.Cassin.

So interestingly, on the day of this Full Frontal test (where i got my last LTHR) I did not hit my true, absolute max heart rate. The highest i got was 197 and it was towards the end of the 20 minute portion. But i spent a lot of time up there, and it went up nice and slow: i think i hit 190 at about minute ten, and 1 minute peak was 196.

I only throw 205 out there because it’s the highest max i’ve recently seen, but it doesn’t happen regularly. The 4DP max (197) is more representative of “normal” maxes. So if you take that, my LTHR is an even HIGHER percentage of my max.

Cycling max HR 180 and LTHR fluctuates between 167-170bpm.


If it helps I’m also using the ‘almost never max’ as well.
Generally the examples of people i this thread are 93, 93, 90 of max. Seems very similar and in a couple of examples higher than your 91

Looks ok for that limited dataset so hopefully just means you’ve got it nailed !!

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haha okay i guess it’s not that crazy after all

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