FYI, Dr Seiler has joined Alan Couzens in regards to DFA not quite being all it’s played up to be.
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Alan’s own coming out:
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I requested a credit in the App Store for the HRVlogger app, after reading the latest news.No point paying for something that claims to do something that has little, to no, meaningful value.
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I noticed this with myself a long time ago. LT1 according to DFA a1 for me is HR 170bpm and power 250W. In reality LT1 is 145bpm and 200W. On LT1 DFA a1 I have above 1.
I have noticed the same. When riding at z1 (based on lactate testing) my hr is capped at 135 and power is around 190-210. When riding at those numbers and using the HRV app on Android I get around 1.3 or when on the Garmin it shows 1.45 to 1.5.
My own experience is similar. Hence I have dropped any thought of using / supporting DFA A1. (lucky for me, else it would have been a lot of effort wasted)
So, what’s better? Just as Alan says, lactate. I track my lactate throughout longer trainer rides, and would do the same if I had a treadmill. (I’m not quite at the same level as a few others who carry lactate readers on rides, yet.)
The point being is that respiration rate and lactate are the coming tech for tracking health and intensity. In fact Dr. Iñigo san Milán and others feel that a continuous lactate monitor would be far more useful than a CGM. The tech for that isn’t quite there yet but it’s coming.
Side note re. CGM: Glucose change is a very late, downstream effect of metabolic processes. (Dr. Peter Attia has found personally and in his practice that only the G6 is accurate–1-2%. Those based on Abbott Libre, i.e. Supersapiens, have error up to 20% which alligns with their own allowable error and my experience.)
Lactate is more upstream, and RR is showing to be excellent for setting intensity. Lactate levels have to be calibrated per user. The Norgies and Pogačar have very low lactate levels (2-3mmol/L) even at higher intensities because their mitochondrial density is so good. Many people having resting levels much higher than the afore mentioned athlete’s Z2 and even walk around with levels above 2mmol/L.
As Marco Altini’s post explains, DFA-A1 is not necessarily useless, it’s just that a fixed, universal threshold seems a poor indicator of exercise intensity.
There may however be value in, for example, checking your day-to-day variations of DFA-A1 for a fixed heart rate or power to have an idea of fatigue (if it’s low, don’t push too hard).
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Agreed. Like everything, make informed decisions rather than using a screwdriver as a hammer.
I can check the day to day variations in other metrics like HRV or resting HR as well as the most important one… how do I feel?
No need for another app that can the same thing.
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There’s a podcast on using dfa for individual tresholds but it’s in Spanish and I don’t speak/understand Spanish. I’m really curious what’s discussed in here. If anyone has/finds a translation, please post it here.
This is the best podcast I've heard about DFA alpha 1
— Marco Altini (@altini_marco) March 8, 2022
Well done @arjona_manu, @lmagallego, and @inigo_tolosa_12
No absolute thresholds, no generalizations, controlled protocols, and using it consistently within-individual, which can be informative
A direction I can get behind https://t.co/eTbWgonnpL
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I posted a while ago that this all looked very dubious
Any attempt to get anything useful or actionable myside always left me with the feeling that the foundations this was based on was dubious and any sort of corellation was most likely observation bias.
I started HRV monitoring in 2017 using a medical grade ECG and single channel method using Polar HR strap (I have data that runs all the way back to prove it). I also started using it before some individuals (names withdrawn) were seen publicly tweeting about HRV repeatedly. It always felt from reading some of their overly zealous tweets on HRV like these so-called coaches were either personally invested in HRV through their affiliations or indirectly looking for a new hammer to hit old nails because their projects weren’t moving in the right direction. That’s a problem for the consumer of information.
What I can share with you is that as an amateur researcher, I was simply studying data on my home PC on my own engineered Excel sheet with an open mind and trying to understand what the data means for me. Along the way, I read tons of original journal articles right from the 1960’s to piece together clues what the metrics mean and which direction they can behave under what circumstance. Despite all that, I cannot, with any certainty, say that I know 100% what I’m looking at. I lean towards the idea and the simplicity of “reading your own body” and making an on-the-fly decision as being much superior to HRV monitoring. Yet, some background research into HRV and my data is on-going…
What I’m trying to say here is that our chief problem is not how to get data, its that we have too much data and we are struggling with how to interpret it. This is the issue with HRV.
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