For those interested in cutting edge HRV research and development, an interesting Web based conference is set for 2 weeks from now. Unfortunately, it will be mostly in German since the bulk of the speakers are from that country.
However, my section will be in English and I am placing it below for direct view. It is a presentation speaking about the use of DFA a1 for exercise intensity assessment and especially regarding zone 1 demarcation. I'll be going over some practical methods to obtain the aerobic threshold (VT1, LT1) using heart rate variability and some of our current research interests.
Heart rate variability during dynamic exercise
- Firstbeat VO2 estimation - valid or voodoo?
- Heart rate variability during exercise - threshold testing
- Exercise in the heat and VO2 max estimation
- DFA alpha1, HRV complexity and polarized training
- HRV artifact avoidance vs correction, getting it right the first time
- VT1 correlation to HRV indexes - revisited
- DFA a1 and Zone 1 limits - the effect of Kubios artifact correction
- HRV artifact effects on DFA a1 using alternate software
- A just published article on DFA a1 and Zone 1 demarcation
- DFA a1 vs intensity metrics via ramp vs constant power intervals
- DFA a1 decline with intensity, effect of elevated skin temperature
- Fractal Correlation Properties of Heart Rate Variability (DFA a1): A New Biomarker for Intensity Distribution in Endurance Exercise
- Movesense Medical ECG V2.0 Firmware brief review
- Movesense Medical ECG - improving the waveform and HRV accuracy
- DFA a1 and the aerobic threshold, video conference presentation
- DFA a1 - running ramp and sample rate observations with the Movesense ECG
- DFA a1 calculation - Kubios vs Python mini validation
- Frontiers in Physiology - Validation of DFA a1 as a marker of VT1
- Rest Day with HRV Logger
Hi! I'm a premed student doing research on VO2max in varying temperatures for my ExPhys course, and your posts have been super helpful! Thank you!ReplyDelete
Hi Bruce. Thanks for the material you publish. I followed your protocol to find my aerobic threshold with HRV Logger and got surprising results. In order to get to the 0.75 level I needed to increase my HR to the 165 to 170 area. I repeated the test a few times and got similar results. I was around 170w at that time. Can these numbers make sense? I am around 50 and trying figure out how to confirm these results. Thanks.ReplyDelete
Hi Arthur, a couple of comments. First, make sure you are not seeing too many artifacts (above 3%). Second, hrv logger employs a different detrending algorithm than kubios which might cause that. I recommend either Fatmaxxer, Runalyze or AI Endurance for optimal accuracy. Let me know what you come up with. Age should not be a factor.ReplyDelete
Thank you Bruce. I will try the Fatmaxxer, as it seems to be the only real time a1 out of those three. What protocol do you recommend for finding my aerobic threshold on the Fatmaxxer? Thanks.ReplyDelete
A friend just posted this great video which may help - https://www.youtube.com/watch?v=AlrHMDPsObcReplyDelete
See my post on best practices for Runalyze for ramps to do - http://www.muscleoxygentraining.com/2021/05/best-practices-for-runalyze-and-dfa-a1.html
Hi Bruce. I tried the Fatmaxxer and got similar results to the HRV Logger. Mid 160s HR for a1 of 0.75. I am still a bit puzzled by these results. Do you think it’s worth trying a lab or these numbers don’t seem that outlandish? Thanks.ReplyDelete
I'm looking at your comment again- " In order to get to the 0.75 level I needed to increase my HR to the 165 to 170 area. I repeated the test a few times and got similar results. I was around 170w at that time" - The 170 watts is certainly feasible but that HR is mighty high for that sort of power. I'm unsure what is going on, sorry.Delete
Hi Bruce. Thank you for all the effort you put in to this very informative blog- what a great resource to geek out and find many more rabbit holes ;-)ReplyDelete
About HRV and DFA: I have not had too much luck with either (collected HRV data for 2 years+). I did manage to get better data after reading your blog by switching to bluetooth (was always wondering how to get rid of the RRx2 artifacts using Garmin devices with ANT+).
Do you have any info on why DFA might not work with some people? I have done multiple tests (using HRV logger and runalyze). For running I can't seem to get DFA to be higher than 0.7, while in cycling I have to go as high as "SweetSpot" to get DFA below 0.75. On my normal "Z2 rides" DFA hovers around 1.3
If the a1 seems too low while running, you probably have the "low a1 while running" issue (there are some posts on that). Use your cycling data instead. If you have clean cycling data from a Polar H10 with a1 not dropping below .75, that is unusual. If you share a link to the data (fit file) I will take a look.Delete
Here is a link to the last outdoor ride. First interval is the warmup. 2nd is at assumed VT1. 3rd is above assumed VT1 (this feels more like lower tempo, would be tough for say 4hrs). 4th is at my "routine endurance power".ReplyDelete
I looked at it in Kubios - https://www.dropbox.com/s/z2r9h7xcmbzdc6p/blog%20data.png?dl=0ReplyDelete
There really is not much dynamic range of HR in the session (120-140 bpm). I suggest an incremental ramp either using Zwift or the old fashioned way (manual control of power, start at 100w, 3 min stages with 30 watt rise per stage to your FTP power).
Thank you very much for taking the time, Bruce!ReplyDelete
I will do a more "formal" test on the trainer as per your protocol.
However, I am pretty sure (also from past lab data) that 185 Watt is already above my VT1 and Fatmax with DFA being around 1.0 for the interval. I know from another ride, that I would have to be working at around SweetSpot to get DFA to 0.75.
That's why I was interested to find out if you found any patterns with the data from people you have had in your study where this method does not work.
let's see the ramp data before deciding the method does not work for you - it simply could be off several bpm from your thresholdDelete
I will be using trainerday, which can do incremental or progressive ramps.Delete
So just to be sure: What is preferred incremental steps eg. 100W, 130W, etc. Or a continual rise of 10W/min?
If you can do - "continual rise of 10W/min" that would be bestDelete