As you can see, I did this on erg mode. The first increment was a warmup, which admittedly should be longer next time. The next three increments were 15 minutes each at 190 W, 180 W, and 170 W. What I find interesting is the heart rate drift. You can see the first shows some upward trend, the second is basically flat, while the last increment actually goes down as the interval goes on. The little HR jiggles were me reaching for my water bottle and coffee
With a longer warmup and perhaps longer increments, can this methodology be used to estimate LT1? Any thoughts @ryan, @trevor, @ThermalDoc?
Thanks for sharing your results. That resting lactate is quite high, but once you started it seems like it calmed down and showed more appropriate values. I would think that 270 watts is a reasonable place to have your LT1. How long can you generally ride at that intensity?
As for LT2, yes, probably around 300. How does that level relate to your performance on the bike?
You do have quite a high ability to go hard and produce high amounts of lactate. I don’t think XC would be out of the question.
What does your HR distribution look like currently?
Not knowing much more about your history, I see this lactate curve and immediately thing you have decent aerobic capabilities, but rely quickly on carbohydrate metabolism and fast-twitch fibers when you get to race pace. I would wonder about your ability to recover from repeated hard efforts above threshold, and would also ask how many years of riding you have under your belt so far.
Hey @SteveHerman, cool trial you did there and thanks for sharing it with us!
That first 15 minutes it looks like it took about 5 mins or so for your HR to stabilize (maybe related to your suggestion on a longer warm-up next time), but I would consider that a steady state response that you achieved. I actually would not consider ay of the response upward trending and it seems as though the HR responded appropriately to the power reductions as the protocol went on.
So is 190W a reasonable LT1? Maybe, but I’m not sure what things look like for you at 200, 210, or 250 watts, so it’s a bit tricky to say with certainty. Really interested to hear other thoughts on this too.
I was informed of this paper: Estimation of the Lactate Threshold from Heart Rate Response to Submaximal Exercise: The Pulse Deficit by Roseguini, Narro, Oliveira, and Ribeirio from 2006.
The Bottom line is subject were given a ramp test with blood sampling to determine LT1 and LT2 (sounds fairly standard). Then the subjects performed several 8-minute steady load intervals while heart rate was recorded. Then the total number of heartbeats for the first 4-minutes of the interval were subtracted from the total heartbeats of the second 4 minutes. This number was called the Pulse Deficit, or PD.
The previously determined LT1 matched up with a PD of less than 25. Based off my eyeballing the included graphs of the data, the average PD at LT1 seems around 12 with a range of 5 to 25.
For LT1+30 watts: the average looks to be 40-45 with a range of 30-55.
LT2 looks to 70-75 with a range of 60-100.
Max power: 85-90 and a range of 60-110.
I’ve played with this protocol (N=1 sample size) a couple of times and my data and RPE tend to generally agree with the conclusions. The last interval was at/near my FTP (maybe even pushing into VO2) and the PD data matched well with RPE, meaning after a couple of minutes I’m thinking “man this is work” as I watch the hr rise.
Does my LT1 agree with the power where a PD is 25? Probably not; but, I will say that it does seem like a reasonable ceiling. All of the intervals below that point felt pretty easy and the ones above took concentration. Of course the “best” combination is to get LT1 and LT2 tested in a lab and correlate this empirical testing for future use. Now all we have to do is contact Coach Ryan about lab testing.
If anyone finds this interesting let’s continue; otherwise, I’ll leave the input to those with a broader base of experience.
Marco Altini of HRV4Training has an iPhone App which logs something called Detrended Fluctuation Analysis (DFA) which seems to show a value of 0.75 for something called Alpha 1.
I have no idea whatsoever what all that means except that I tried it out and on the couple of tests I’ve done it aligns really closely where I estimate from other means where my LT1 heart rate is. Nothing however about LT2. At $7 for the app it’s a somewhat cheaper than a lactate meter. The link to the app is on a tweet lower down the thread.
LT1 265-270 W would be hard, but manageable for 1,5 - 2hours i would say. As a HR point of view 160-165bpm is at my 82-82% of my max(195). So for LIT rides, a would never go that high, but for 240W-245 maximum.
At LT2 300W , i have to be very well rested , even to be able to pedal for 30min at that level, it sits really at my 1 hour max hr (175).
Your assumption is spot on, i rely on CHO big time, even just above 270W (might be also due to the fact i’m a vegan?) As hard efforts recovery… i find 30/15sec HIIT at 390W waaaay easier than 4x8min at 320W. I think i never managed to did all 4 sets at that high watts.
I ride more seriously in the last 8 years or so. (i’m 39 right now @66kg)
Yes! I use this! It closely matches my estimated LT1 too. I like the way you can monitor the DFA Alpha 1 in real time during exercise using Marco’s HRV Logger app. Definitely worth a look. I also suggest providing feedback to Marco as it’s very new research and feedback is important. I also use Marco’s great HRV4Training to monitor my internal state on a daily basis.
I noticed that my LT1 HR is quite different for cycling and running. Now some may think that is obvious, but it wasn’t for me until I saw it in real time …
I use a Garmin HRM Pro HR strap. It generates the RR Interval data required for the calculations (not sure about the Tickr) and can connect to two Bluetooth devices. I connect it to the HRV Logger app and to Zwift (for my winter training). I guess you could achieve the same using Bluetooth and Ant.
Apparantly the Ticket does not work when connected by Ant+ but does when connected by Bluetooth. I use a Tickr and it appears to work OK. This a graph of a brief step test I did.
I’ve got a Tickr, Bluetooth, and a pulse. I should be good.
I got a promotional email from HRV4Training (Marco) about the new app right after it appeared on TR forum but didn’t want to buy a new strap, etc. I also wasn’t following that thread as closely as I do others, so I may have missed the part about the Tickr…so apologies.
@ryan - hopefully you don’t mind my resurrecting this one. I did this test (below) a few years back now, but coincidentally my ‘threshold’ is about the same now. Is it possible to identify LT1 (in particular) from this? Obviously I’m four years older, and I also weight about 3kgs less. My training regime is broadly comparable to what i was doing then, as far as I can recall.
You’ll note one of the blood lactate values look a little bit odd. It’s a bit late to ask the people who undertook the test what happened there. Could it be physiological (I do recall relaxing a bit into the test), or more like a measurement or data entry error?
Interested to hear your and other’s thoughts. If I do another test in future is this a reasonable protocol, or would it be better to have something a bit more granular to be able to pick out the LT turning points?
HI @steveneal, this is the only other info I have unfortunately:
The test consisted of a 3 minute warm up at 150W, followed by 3 minute stages, beginning at 180W. The power then increased at the beginning of each stage until lactate threshold was reached. At the end of each stage, your heart rate, blood lactate and RPE were recorded before increasing the intensity. Throughout the test we asked you to maintain a steady and comfortable cadence.
Hi @Mr.B, thanks for sharing that test result. Thanks to @steveneal for asking those important questions too. Knowing the analyzer and if it the calibration was checked beforehand is very helpful, along with more information about the protocol. I do see that odd lactate value of 1.8. This can occur relatively early in a test as the rider warms up. So yes, to your question, as you settle in and aerobic metabolism ramps up, you can sometimes see that decline in lactate. Here’s another example of that occurring after the first stage - for reference I normally use 4 min stages and start relatively conservatively depending on the athlete.
In this test case, a 3 minute warm-up + 3 more minutes at 180 is very short in my opinion. So having lactate drop from 2.1 to 1.8 like that does not seem out of the ordinary, especially since it is relatively close to your resting measurement of 1.6 mmol/l and you report feeling like you relaxed into the test at that point.
In terms of LT1 from your data, it’s hard to say for sure based solely on the table. I would suggest a lower starting power to get a more pronounced baseline lactate response. At 150 watts, which sounds like it was intended to be a warm-up intensity, your RPE response of 12 is getting close to “somewhat hard” on the RPE scale, which I would consider too high for warm-up. I’d like to see numbers in stage 1 that would approximate 8-11 on the Borg RPE scale. However, those details aside, and not having anything other than the numbers in the table, I would conservatively set an LT1 range for you between ~140-170 watts or ~120-135 beats and then suggest re-testing with a slightly longer warm-up and easier starting stage to see if you can get any improved baseline response.
@ryan thanks for that response. I agree in retrospect it was a surprisingly short warm-up, certainly I’d never try to do an intense session with such a short one. Your LT1 estimate sounds about right to me, and I’ve commented on another thread how that feels like the level of effort where things change. I think I’ll try to get another test done - unfortunately it won’t be with you guys as I’m in Europe, but I will look more closely into their protocol and especially the warm up length and proposed wattages (esp. the beginning one) and durations. Are there particular analyzers you recommend, or should be avoided in your opinion?
@Mr.B I agree with all the points @Ryan made, especially starting the test easier (likely 100watts) and using 4 minute steps.
I have had very good luck with Lactate Plus (out of USA but have had a few people in Europe get this as well). You could also look into the Scout if there is access to the analyzer and the strips for testing.
I agree with @steveneal in terms of the analyzers. I used the Lactate Pro (old one) in the past with good success. Now there is a Lactate Pro 2 available in some locations. Also used the Lactate Plus, which was initially a backup in the lab if we had trouble with the Lactate Pro, but have since moved to the Lactate Plus exclusively.
Quite a timely resurrection of a previous post on identifying LT1.
I did a test today to accurately identify LT1 for an upcoming block of work after a couple of recent races. I used a typical MLSS protocol: 10 mins steps, taking lactate values at 3 and 9 minutes looking for an increase in lactate greater than 1mmol/L between 3 - 9 minutes.
I’ve taken lactate readings during a few ramp tests over the last year plus doing the above protocol once in May with LT1 improving from ~200W to ~230W over that time, with LT1 HR typically between 141-144bpm. I did an INSCYD test in July which gave a threshold value 260W. I’ve spent the last couple of months trying to improve threshold in preparation for races, but don’t have an up to date value for it. A few software packages currently have my threshold at ~265W.
I’ve put todays results into a table and included avg HR for the last 30 secs before the 9 minute reading. I was expecting LT1 to be similar to my last test but I’m unsure what to make of todays test.
Sept 2021
As you can see from the table I didn’t get an increase in lactate of greater than 1mmol/L in any of the steps. If I was going to just determine LT1 from lactate values I’d pick 225W, but if take previous HR data into account I’d pick 245W for LT1.
@PeteD I don’t use this protocol but based on your table I would agree 220 to 225w. There is no lactate increase at 220w, but there is a slight increase at 230w, so using 220 or 225w would likely be safe.
I would always use 100w start, 4m per step, 25w increase.
Based on the best from May there is lactate increase at the 215 watt step so I would say at that time LT1 was lower than 215w.
The heart rate could be lower now due to better respiration or increased stroke volume from your training since the May test.
I would recommend starting at a lower wattage, and always starting at the same wattage no matter the protocol you chose, as well as repeating the same wattages.
In May you chose 215, 225, 235 so maybe repeat those again but continue you higher to see the change in trend.
