Training & Nutrition - Advice on Lactate Threshold HR

I've got some of my first ever TTs coming up, so I thought I should try to figure out what my LT HR is.

I just did a test today that I've seen recommended in a few places:

- 15 min warmup
- 30 min TT with the average HR of the last 20 mins being LT HR

My result was 180 BPM, but I did this on the trainer. I tried to push my hardest, but it seems I could have gone slightly harder if I was on the road doing a TT.

I've got heart rate data going back pretty far. Here are some examples of when I felt like I could not push any more:

12 min @ 192 BPM average
1 hr 45 min @ 184 BPM average
5 hr @ 172 BPM average

The first two lead me to believe that today I reached a number that is too low due to being on the trainer.

Those three results are from the road in a competitive atmosphere and the 2nd and 3rd were after a few days of rest.

I'm not looking for an exact number, but I'd like for it to be fairly accurate. It seems somewhere around 185 BPM would be more accurate based on the other data.

Thoughts? Am I doing it wrong?

I've heard you're better underestimating than overestimating. Though your LT does change -- and with periodization that is to be expected. So an old result from, say, the height of the season, may not be as good now. Can you deal with using this number till you can retest under better conditions after a couple of training cycles ?

Yeah, I can. I am just beginning to race, so the TTs don't even count for me. I am just trying to learn how to maximize TT performance for when it does count.

The main reason I posted is to get a better understanding of the test used to get this number. It seems that if I should take my average heart rate going all out for 20 mins, that it should be higher than going all out for 1 hr 45 min.

I am in better shape now than during ride number 2 above. I might try to repeat the test outdoors and see what I come up with.

Indoors, you're much hotter than outside (usually) since you don't have enough wind cooling you down. That raises HR relative to the same effort outdoors.

I did the test indoors primarily because there are no obstacles / surprises that might cause an interruption in effort. I am usually able to maintain a slightly higher heart rate outdoors than I am on the trainer though.

Anyone want to weigh in on the 1 hr 45 min @ 184 BPM average? It seems that if I was able to do this, then my latest tested LT HR is too low. I am in better shape now than I was during the 1 hr 45 min effort, but I was better rested then.

Anyone want to weigh in on the 1 hr 45 min @ 184 BPM average? It seems that if I was able to do this, then my latest tested LT HR is too low. I am in better shape now than I was during the 1 hr 45 min effort, but I was better rested then.I found it difficult to pin down LTHR based on one test as there are many factors that can affect the outcome. On a long race/ride you will likely be hot and dehydrated both conditions will raise your HR but not your power. I know if I look at my HR over a 20 min period at the end of a 3 or 4 hour ride it is generally higher for the same power output than an equivalent period at the start.

If you're planning on using LTHR for TT pacing I'd be wary of using too high a number as you may end up going out too easy. Probably better to just use PE or better yet pick up a power meter.

I've trained with hr since the late 80's and am familiar with the problems of the OP. Short answer is, there is no short answer - you are in the zone of uncertainty.

When I ride tt's, I just make sure I'm rested and feeling good, and in the initial miles try not to get above the threshold zone.

But if I'm feeling really good after the first few miles (and depending on my pacing strategy for the tt) I might just open it up and go hard based on perceived exertion, ignoring the hr.

Which, IMO comes down to the real way to go fast in tt's: make it hurt and ride as fast as you can.

My best tt results have come from that strategy; and during those rides my hr was several beats above my "usual" threshold zone.

I've trained with hr since the late 80's and am familiar with the problems of the OP. Short answer is, there is no short answer - you are in the zone of uncertainty.

When I ride tt's, I just make sure I'm rested and feeling good, and in the initial miles try not to get above the threshold zone.

But if I'm feeling really good after the first few miles (and depending on my pacing strategy for the tt) I might just open it up and go hard based on perceived exertion, ignoring the hr.

Which, IMO comes down to the real way to go fast in tt's: make it hurt and ride as fast as you can.

My best tt results have come from that strategy; and during those rides my hr was several beats above my "usual" threshold zone.

This makes sense. I think I'll stick with the 180 as a rough estimate for now and use PE to determine where exactly I think I should be at any given time.

There are several interesting points in this thread.
First of all, it should definitely be more difficult to raise your HR while indoors on a trainer. Your body is less affected by the physical environment. Also, there's something to be said about your level of awareness and sensory perception when riding outdoors, also making your HR easier to elevate.

The years of data that may be kept on record prior to training specific to LT, should be considered a completely different "ball of wax". Sure, you can push to a certain limit, and hold your performance there...but this has a few other factors to consider. Did you always maintain the same fuel storage and intake intervals, were you always properly hydrated, was your sleep schedule consistent, etc.

Perceived Exertion (PE)- this can also vary. A recent study done by JMU (which hasn't even been published yet, I think) found that certain amounts (relative to body weight) of caffeine can actually increase performance while the RPE does not change. Could this be due to vasodilation, or the analgesic properties of caffeine? I'm not sure. So, does your caffeine consumption always stay the same from day to day...and especially prior to, and during your rides? Stress levels, sleep, mood, overtraining....also can alter your PE.

There are, as you know, a few different "accepted" methods of determining your LT in the field. Joe Friel and Chris Carmichael both offer widely accepted tests. Although they differ in methodology, I've found the results to be the same, regardless. During the 30 minute test mentioned earlier, I would eliminate a prior warm up. Since you're only capturing the last 20 minutes of the test, the first ten should suffice as a "warm up" period.

And finally, regarding HR during competition and competitive TT's: HR during competition can be deceptive. Due to the extra "stress hormones" that are released, your body can maintain HR's a little differently than during training. The important thing to remember, is simply fuel storage capacities and limits.

Feel free to read this: http://www.scribd.com/doc/25586695/Basic-Exercise-Physiology-Cycling?secret_password=1fn4z6lasmy01r2161mk. It's VERY basic, but may help to give a little more insight.

I did the test indoors primarily because there are no obstacles / surprises that might cause an interruption in effort. I am usually able to maintain a slightly higher heart rate outdoors than I am on the trainer though.

Anyone want to weigh in on the 1 hr 45 min @ 184 BPM average? It seems that if I was able to do this, then my latest tested LT HR is too low. I am in better shape now than I was during the 1 hr 45 min effort, but I was better rested then.


Well, I can tell you that I have a _really_ hard time holding big heart rates inside, but no problem outside. I think cooling has a lot to do with it, but psychologically it's just completely different. I always test low indoors.

If I were you, I'd use a number of about 185 as a starting point and work from there. If you need to shift it up a beat or 2 during the season, then do so. I'd also try to do a 30 minute test outside when possible to get a better idea of the correct HR.

Well, I can tell you that I have a _really_ hard time holding big heart rates inside, but no problem outside. I think cooling has a lot to do with it, but psychologically it's just completely different. I always test low indoors.

If I were you, I'd use a number of about 185 as a starting point and work from there. If you need to shift it up a beat or 2 during the season, then do so. I'd also try to do a 30 minute test outside when possible to get a better idea of the correct HR.

This has been my (admittedly unscientific) experience as well. It's a good starting point, but keep looking at it.