I did 10 min intervals but the guy at the HRV app said 6 or 8 min is sufficient.
First test done - indoors on rollers, Polar H9 & Android via BT.
Started the ramp at about 45% FTP and worked on 6 min intervals. Gradual progression until I saw Alpha 1 dip <0.75. VERY surprised with the result - 154bpm and about 80% max HR - and roughly the lower end of tempo power. for my outdoor riding usually.
Iām ignoring the actual power numbers from the test as HR was low relative to my power output today (3 big rides of 450 TSS in the last 3 days) so some fatigue obviously present although no perceived fatigue at all.
The other surprise is that Xert has my LTP modelled right at what Iād expect for 154bpm. I have seen a lot of people suggest the Xert number is high, and I used to think that, but it looks pretty spot on. YMMV
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I used the Python script an ran it on my 2021 base rides files. While I donāt get to see alpha changes in real time as I exercise, the script uses some basic linear regression to derive the aerobic threshold heart rate. Interestingly enough, the prediction is almost in line with coggan Z2 limit 83% of LTHR, consequently very far from Frielās 89% LTHR
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Interesting - my test today with the HRV logger app is exactly 89% of my LTHR. I hadnāt read Friel suggesting it was 89% before.
My LT1, using the HRV Logger came out at 143 bpm which is 82% of max. Coggan said 83% max and Seiler said ātypicallyā 75% of max. So, it appears tat I am right in the zone.
Would be interesting to hear at which percentage of ftp for you guys (who have actually tested) this lt1 falls.
I think thats a little harder as the power at the HRV LT1 isnāt going to be constant. The guys behind the HRV app also make it clear the results are going to change based on things like temp, caffeine, humidity etc etc.
As a ballpark, if my HR of 154bpm was correct in yesterdayās test then Iād expect a power of about 215w so that would be about 78% of FTP right now. Off for a steady outdoor ride today so may see how that correlates today.
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Mine is around 75% of FTP on an average day, but sometimes itās higher and sometimes itās lower. Matches up pretty well with how Iām feeling also.
Iāve found it to be a useful tool.
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That is exactly what Iāve found using the Alpha1 thing both in terms of how much higher it put my LT1 compared to what I thought it was and how close it was to my Xert LTP
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This talk test and nose breathing does not work for me. My La measurements are super consistent but relating them to nose/talk is impossible for me.
How does the HR form lactate test compares with your corresponding Coggan 83% LTHR or Friel 89% LTHR levels?
Question for you @sryke, because I really struggled with the talk/nose breathing ātestā as well.
Have you tried breathing rate? Does your LT1 correspond to breath count?
(Fun fact: I believe one of my very first posts on here was asking sryke about the breath testā¦I thought I got it back then with the talk testā-I didnāt. Not even close. Deja vu)
I donāt know my LTHRs. Havenāt done any FTP or similar testing in a very long time.
I donāt think I have. I already lost interest when just paying attention to breathing. I already struggle when just sitting here and wondering how my breathing is.
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Iām going to close this topic (LT1), for meā¦Itās very interesting that I had empirically discovered it before even knowing what a training zone was. Iāll leave with the following lessons:
- Ride you bike a lot, and for long sessions if you canā¦develop the āfeelā.
- If you want guidelines, Cogganās and Frielās top of Z2ās are good enough.
- The most promising and interesting easy measurement is alpha1=0.75
- Go the lactate test route if you really enjoy the process of measurement and derive value from that. Otherwise not necessary.
- Donāt do it by % of FTP.
Cheers.
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Todayās ride was what Iād call āendurance plusā where it kind of rides the line between endurance and tempo, but not really proper tempo where it takes a good amount of concentration to maintain. A hard 4 or an easy 5 out of 10 on the RPE scale. I was pretty fresh and off a good ride yesterday where I set a 60 minute PR coming out of a short block of rest/easy riding.
So letās just call it 275-300w and 160-162bpm, which as a range is 77-85% of mFTP, roughly 80% of max HR, and about 90% of LTHR.
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And thereās also a reason people are slower when it is hot, ie the extra physiological strain of cooling your body lowers your ability to make power. There are some who dont, but most have impaired fitness in the heat. That is why you should listen to your body, if you stick to power, you are no longer in the right zone for the intended workout.
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Like altitude you may experience a temporary drop in FTP when the weather gets hot, although you can get heat acclimated over several weeks and return to near normal FTP. Therefore what to do about hot weather is up for debate:
Former pro Evan Huffman grew up here, and has interesting feedback in the comment section of that CTS blog post.
Also some very good info on that Triathlon Show podcast episode 138 (and 261).
Not sure I am adding anything meaningful to the debate here other than my thoughts but I have been playing around with ballparking/ assessing my LT1 with the means at my disposal eg. no ability to use HRV Logger or blood test currently.
As a newbie to this, I started off with this spreadsheet (see below) and pumped in my numbers to get an estimate of where LT1 is (circa 75% MHR according to it) and then have done a few rides to see how things feel when I get around the associated %FTP (224w for me) and focused on any changes in RPE and breathing etc.
https://twitter.com/peter__leo/status/1350437489568317445?s=21
Today on doing fletcher I noticed a pretty distinct change in my breathing rate and HR as I stepped up into a interval at circa 223wā¦pretty much spot on with the above estimate.
Anyway, in summary the spreadsheet seems to of given me a pretty good estimate to work with I think based on this very primitive in workout testing. My MHR has not changed since the start of the year so interesting to see how my LT1 has moved right in the year to dateā¦
Just thoughtsā¦
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Just adding my 2cents on A1 = 0.75
For me it comes in around SST effort/HR. Have spent quite a bit of time debugging and trying different things. I am just coming back to fitness after a break and 0.75 does equal my old LT1 (if I had to guess).
Will test is once a month and see if it starts to align to what I think LT1 is.
New research paper is out:
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