Calculating LT1 and LT2 approximately without a blood test?

You do realise this is an app for locating and enabling you to stay below LT1? There’s no benefit to obtaining readings once you go below 0.75 alpha1. Once you’re under you’re under, there is no use for it in that zone.

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Yes, I do realize the purpose of the app, but before I actually use it or just accept that it is valid I have been testing it to see how it correlates to true and valid data I have for myself in the form of an actual blood lactate test, so while I appreciate your concern and explanation, it’s not needed.

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That’s good, just checking. Once you’re below 0.75 there doesn’t appear to be any correlation with anything mind, it’s just low and doesn’t really relate to any particular level. That’s what I’ve read anyway hence the comment.

What is the evidence that training just below LT1 is better than training at it or above it?

What about training way below LT1 - is that better or worse?

Prediction: the use of HRV to estimate LT1 to prescribe training will prove to be just another fad driven by the proliferation of wearables.

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So now you have both lactate and HRV data. Where are your LT1 and LT2?

We have found most of the low hanging fruit so finding new useful metrics will be hard and might lead to many dead ends. I think it will be worth it though in the long run. Machine learning can greatly help with this as many metrics might only have a small impact or only have an impact under certain conditions.

N=1 self-study; high stress(training+life events) results poor sleep(quality and length), poor recovery, low mood, low hrv.
Training below LT1(even high volume) increase my hrv and improve my sleep and mood provided proper refueling. Effect is even greater than with full rest day.
Training at LT1 seems to create same kind of sympathetic nervous sys. responce as with tempo, threshold, hiit and sprint workouts, but milder.
For me training below LT1 allows to keep volume somewhat high without overtraining and gives ability to shift ANS to parasympathetic state after high intensity training days.

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You should tweet Inigo San Millan about your reservations about training at LT1

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Appeal to authority is a very weak form of argument.

My questions therefore remain unanswered, and my prediction stands.

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But hearing an authority’s argument would be interesting :slight_smile:

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I think that, unless you have a well trained aerobic system, the LT power is a bit of a misnomer. LT1 is a heartrate threshold. What I have seen is that if I ride at the power where I see DFAa1 first hit 0.75 I will see decoupling of the power and HR over time- the power is constant and the HR rises and DFAa1 drops. I talked to the guys at HRV4Training and they said the same thing that I heard in a podcast by Steven Seiler- if you want to train in Z1 (in a 3 zone model) at a level close to LT1 then you should use heartrate rather than power as a guide. Over time, the amount of time you can spend at the initial LT1 power without decoupling will increase. Seiler said that he was training his aerobic endurance and that it was hard and he was just getting to the point that he could work near LT for 90 minutes (if I remember correctly) with getting significant decoupling.

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this is well known before Seiler, HRV4 et al. It’s interesting how little credit HR gets in this forum, given that is the only measure of internal effort we get.

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Agreed. Adding with edit- The Sufferefest Half Monty ramp test has two parts- a ramp test basically identical to the TR ramp test followed by a 20 minute heart rate constrained section that is well below the LTHR. In the second section you keep HR in about a 10bpm range by adjusting power. For me, at least, the power decoupling is obvious during this interval. SF uses this data to fine tune the FTP estimate.

I’m not sure this is as true as you are implying, for example when I’ve been training at temperatures of 61F / 16C and then go out on the first hot day at 90F / 32C. In the hot conditions my heart rate will increase due to additional internal workload to support evaporative cooling.

I’m all for using power in conjunction with heart rate, provided you have gained some understanding of heart rate dynamics in response to various power loads and durations.

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So the question is…if you want to do, say 3h of endurance, z2, lt1, etc. during these hot conditions, do you stick with power or listen to the heart rate?

depends on:

  • what phase of training
  • other work in the week
  • where I am in the process of heat acclimation
  • my current tolerance for zone2-of-7 (zone1-of-3) strain

But typically I use power for aerobic endurance rides. Only under special circumstances will I set a heart rate cap. Both my coach and I would rather be practical and determine power for endurance efforts based on trial&error using post-ride feedback and following workout’s pre-ride feedback, as opposed to chasing some metric like DFA-alpha1, lactate testing, or ventilatory testing. I’m now in the habit of making notes after every ride, it is surprisingly useful. Outside of the occasional outlier workout, I believe if you pay close attention to your body it is far more practical to use power than HR. That said I value looking at soft metrics like HR zones, aerobic decoupling, heart rate recovery after completing certain types of intervals, etc.

Out of curiosity I’m going to try HRV Logger and see what DFA-a1 says, but not let the results change how I’m doing workouts. Just like I’ve been reviewing the HRV derived Performance Condition metric (FirstBeat algorithm on Garmin 530) on every ride for over a year.

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I use HR mainly for my ISM style AeT rides. I use power to “validate” my body feel, the ultimate control variable. I find it important to have some control and checks, otherwise total work load will be too high.
Figuring how much I can tolerate under an exercise-addiction-driven-high-volume program has been quite a journey for the last year. Because intervals only make fun when you can hit it, when you’re fresh. The same for these ISM AeT rides, no fun if your legs are tired.

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For LT1, I have my own mini-ramp test that bumps the power by 5w every 10 min and monitor it with the HRV Logger and a Polar H10 HR monitor and wait for the first wattage where alpha 1 crosses 0.75. Or… some people will just use 0.77 x FTP. I then confirm the data by doing a 1 hour session at that power output and monitor my HR.

For LT2, I pretty much just do my VO2 & Anaerobic workouts at FTP x 106% and higher.

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and that is the primary ‘test’ in my humble opinion. Do the work, add aerobic endurance as necessary, and don’t compromise the hard work. I’m only doing 8-12 hours/week, and power has worked well for me to meter low (and high) intensity efforts. While others may prefer HR, I happen to prefer using one primary control variable for all efforts.

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I’m doing that ramp test this morning for the same purpose. I will probably do it on the rollers so slightly less controlled intensity jumps but it wont be far off.

Looking forward to seeing the results.

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