[SlowAndSteady]

A while back, I did my training at a pace where I could breathe through my nose and comfortably have a conversation. But I wasn’t improving, so I went to a lab to get a lactate threshold test. Come to find out, I crossed 2.0 mmol/L at 113bpm, which was about 30 beats lower than where I was training.

i “fixed” this issue over the next year through tons of walking then reintroducing slow jogging, and now don’t cross 2.0mmol/L until I’m about 145bpm.

however, this evening I went on just a nice hour long walk. Heart rate started between 95-102bpm, and kept creeping up until it was 115-122bpm by the end of the walk…. Hence telling me via the drift test that I should train much lower than 145bpm.

so which do I go with? Back to walking until I stop drifting more than 5%? Or does the 2.0mmol/L carry more weight? I would have thought the drift heart rate and lactate would both be similar since they are both used to determine aeT

[Seth Keena]

Hi SlowAndSteady,

Thanks for writing in. Firstly, great job improving your AeT and by so many beats!

Did you also do a drift test around the time you found 2mmol/L at 145bpm?

Were you especially fatigued the day of this high-drift walk?

If this high-drift walk was anomalous I would ignore it as just that; an anomaly. It seems that way to me from where I sit. Even with clean, fresh battery chest straps and excellent GPS data I see HR in places it otherwise ‘shouldn’t be’ on not too rare occasions.  Perhaps do another drift test on a treadmill at 115bpm and see what happens.

Drift tests, lactate test and gas exchange tests are all proxies for aerobic threshold and fitness. We have come to prefer the drift test over the other testing means for its excellent specificity and reproducibility. Nose breathing is also a fine method for observation and control. If you’ve not read our most updated article on this subject area : https://evokeendurance.com/our-latest-thinking-on-aerobic-assessment-for-the-mountain-athlete/

-Seth

[Seth Keena]

Hi SlowAndSteady,

Thanks for writing in. Firstly, great job improving your AeT and by so many beats!

Did you also do a drift test around the time you found 2mmol/L at 145bpm?

Were you especially fatigued the day of this high-drift walk?

If this high-drift walk was anomalous I would ignore it as just that; an anomaly. It seems that way to me from where I sit. Even with clean, fresh battery chest straps and excellent GPS data I see HR in places it otherwise ‘shouldn’t be’ on not too rare occasions.  Perhaps do another drift test on a treadmill at 115bpm and see what happens.

Drift tests, lactate test and gas exchange tests are all proxies for aerobic threshold and fitness. We have come to prefer the drift test over the other testing means for its excellent specificity and reproducibility. Nose breathing is also a fine method for observation and control. If you’ve not read our most updated article on this subject area : https://evokeendurance.com/our-latest-thinking-on-aerobic-assessment-for-the-mountain-athlete/

-Seth

[SlowAndSteady]

Thanks very much for the response Seth.

 

i don’t typically track drift carefully since i was so focused on lactate, but i do notice that when i typically started a run at say, 120-125bpm, 30 min in itl be maybe 135-145 (or more if temp is high).

is drift test more accurate than lactate?

 

also, unfortunately nose breathing test has never been accurate for me (i don’t think, correct me if im wrong). My 2.0mmol/l lactate was 30-35 beats lower than my nose breathing when i did the lactate test and remained that way as I improved my 2.0mmol heart rate over time. Even now, I can nose breath at like 160bpm, which is about 80% of my mhr

 

so I think either I’ve been training at too high of a heart rate  at 140-150bpm (based on blood lactate) to make improvements, and need to back down to walking again and use drift test?     Or, I’ve been training at too

low of a heart rate and need to use nose breathing test and run closer to 160bpm

or maybe I should keep using lactate and I’m just not doing enough volume (4-5 hours a week at 140-150bpm for the last 9 months), and that wasn’t enough to make pace improvements from my 13-16 minute miles. Mile pace heavy fluctuation due to temperature

[SlowAndSteady]

Too add, on my long runs (an hour and a half ish), once my heart rate gets to the 145-155 range 30-45 minutes in, I can usually keep my pace from then on without my heart rate continuing to increase at a steady rate

[SlowAndSteady]

Seth, I think I was frustrated and spoke too soon in my post. Sorry. I think it just took 30 min or so during my OP’s walk for the hr to get up to its steady state level, what do you think?

today I tried an actual drift test on a treadmill at a constant speed, walking on an incline. Had jaw surgery a few weeks ago so can’t run yet. Warmed up 15 min, then started the test. Average heart rate of 122 and it actually drifted down in the second half. I found out about the polar beat app’s ability to show avg heart rate over a range, so will start taking advantage of that. It’s probably likely the drift test will correlate with my lactate test heart rates, looking at a couple of my old runs before my surgery, that seems to be the case

[Seth Keena]

I suggest going with the drift test and only the drift test – we have a lot of data correlating it tightly to GET and lactate, but it tends to be more ‘functional’ and is definitely easy to repeat. The above article has all the guidance for the treadmill test and it sounds like you are already seeing it closely track your lactate tests of past. Negative drift usually means the beginning HR was significantly below AeT.

Some folks take more than 15min to warm-up for aerobic workouts, strength, etc. Do what you need to in terms of warm-up.

[SlowAndSteady]

Thanks. I did another drift test a couple days ago, walking on a treadmill on an incline. I warmed up 20 minutes working up to the steady state speed I used, took a 3 min bathroom break, then began the workout.

 

i think this is my last question? Should I disregard the first 5 or 10 minutes of my workout when determining drift?

this is all after warming up:

-using entire 65 minute workout: 132/126= 4.8%
-discarding first 5 minutes: 132/128 =3.13%

discarding first 10 minutes: 132/129 = 2.32%

 

obviously in this scenario, I’m okay if I don’t do any discarding of the initial few minutes. But in many other workouts, I’d be over the 5% unless I don’t take the first 5 or 10 minutes out of the equation.

[SlowAndSteady]

Here is todays workout, which gives a better indication of what i was talking about in previous post, this time whole workout was above 5%.

Incline: 9% for warmup and workout
Warm up 23 minutes before beginning workout, working up to 3.0 mph workout pace.

65 minute workout (not including 23 minute warmup)
Drift: 150/141=6.39%
Drift discard first 5 minutes: 150/143=4.9%
Drift discard first 10 minutes: 150/144=4.17%
Last 37 minutes of the workout, the avg heart rate stayed constant at 150bpm (150/150=0%)

[Seth Keena]

Read this article, namely the parts about drift test; https://evokeendurance.com/our-latest-thinking-on-aerobic-assessment-for-the-mountain-athlete/

It will do 10x better job of explaining your question than I would 🙂

[SlowAndSteady]

Thanks Seth, that is a valuable article. But I’m still a little confused on the question in my last two posts, whether or not the first 5 or 10 minutes after a warmup, upon starting the workout, should be discarded as “bad data”, due to the heart rate drift stabilizing more afterwards for the last 55-60 minutes of a workout.

[SlowAndSteady]

I think I’m all set. I’m thinking the 3 minute, and even the 1.5 minute break between warmup and workout threw off the test results, so I’m assuming I’m correct in discarding first 5 or 10 minutes

from now on I won’t take a break between warmup and workout aside from restarting treadmill

one thing is certain, I take much longer than 3 minutes for heart rate to stabilize at a given intensity. I think that’s the crux of why I’ve been a bit confused.

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