Sunday, March 14, 2010

Physiological Fitness - Lactate Threshold

I apologize for the recent gap in posts. I'm preparing to go to Majorca for a camp next week and so have been up to my ears in work that needed to be done first. This post is a continution of the topic I started last week - the three determiners of physiological fitness. The last post discussed aerobic capacity. This one has to do with lactate threshold.

While aerobic capacity gets a lot of ink in endurance-sport magazines, for the competitive athlete the lactate threshold is what the bulk of the hard training should focus on. Your aerobic capacity isn’t going change a lot if you’ve been training and racing seriously for three or more years. But you may be able to bump your lactate threshold up a lot.

So what is lactate threshold? We need to start with a little biochemistry to understand this measure of intensity.

As your body uses carbohydrate to create energy it creates a by-product inside the working muscle cells called lactic acid. As the intensity of a workout increases this liquid begins to seep out of the muscle cell into the surrounding space and blood stream. In so doing it changes its composition by giving off hydrogen ions. It’s now called lactate. Despite its “bad boy” reputation, lactate is actually a beneficial substance for the body during exercise as it is used to create more energy so that exercise may continue. It’s the hydrogen that is the real bogey man. This is what causes the burning sensation in your muscles and the heavy breathing at high effort levels. Measuring lactate levels in the blood is a convenient way of estimating how much hydrogen is in the body. The more intense the workout, the greater the amount of lactate released into the blood — and the more hydrogen ions interfering with muscle contractions. (By the way, neither lactate or hydrogen ions cause the muscle soreness you may experience the day after a hard workout. That's another of the myths that refuses to die in sport. Some day I will do a post just on such old saws.)

Lactate threshold is sometimes referred to as anaerobic threshold. While sports scientists may argue about the differences between these two terms, for athletes there is little reason for concern. Both are essentially the high intensity at which you begin to “red line.” On a perceived exertion scale of 1 (low) to 10 (high) you redline at about 7 or 8. Whatever your heart rate, power or pace is at this moment is your lactate threshold intensity. The higher this is as a percentage of your aerobic capacity the faster you will race, especially in steady-state events such as triathlons or endurance running races. It’s common with fit athletes for their lactate thresholds to fall in the range of 80 to 85 percent of their aerobic capacities.

Most well-conditioned athletes can sustain this level of intensity for about an hour. Because of this there is a new term created by Hunter Allen and Dr. Andrew Coggan, the authors of Training and Racing With a Power Meter, to describe this intensity – functional threshold. This is the average bike power (functional threshold power – FTPw) or running pace (functional threshold pace – FTPa) you can maintain for one hour. Simple.

If you are using heart rate to determine your training zones, your lactate threshold heart rate (LTHR) is your average heart rate for a one-hour race effort. This is unique to the sport, so your rowing, cross-country skiing, swimming, cycling and running LTHRs are likely to be different. And therefore your heart rate zones will also be unique to each sport.

The body has two ways of improving your lactate threshold as a result of training. It can come to better tolerate the acid and it can also become more effective at removing the acid. As with all aspects of fitness, the way to train your body to tolerate and remove hydrogen ions is by training at your lactate threshold. This, then, is the best marker of training intensity. That’s why I base heart rate zones on it rather than on maximum heart rate.

I hope to get something posted on the last topic - economy - soon but expect this may be at least a week or more. We'll see.

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At March 15, 2010 12:37 AM , Blogger Andrew said...


After reading your post it says that lthr is about 80-85%. Using the 40km tt I found my HR to be 177 and have a max of 193.

This means that it 92%....

Im a 17 years.


At March 15, 2010 4:36 AM , Blogger Justin said...


Great post, thanks for the info! Just wondering if you could write up something about racing triathlons with a power meter? After reading "training and racing with a power meter" I don't know if I believe there numbers for racing since they say you should ride between 95-100% of your FTP. Thanks!


At March 15, 2010 6:07 AM , Blogger Josh said...


Thanks for offering this valuable info here. This post an the previous post on aerobic capacity is a great compliment to the info in your book "The Triathlete's Training Bible." I have a question regarding aerobic threshold workouts. Especially with running, I find these runs to be quite easy, and probably would had called it a recovery run before learning the term aerobic threshold run. Do I need to re-evaluate my aerobic threshold pace? At this point I'm using the chart and my current 5k and 10k pace.

At March 15, 2010 7:11 AM , Blogger Joe Friel said...

Andrew--80-85% of VO2max, not HR.

At March 15, 2010 7:13 AM , Blogger Joe Friel said...

Justin--That would be about right for a sprint to Oly distance tri. Seems like I've written quite a bit on power for tri. I'll have to look around in archives.

At March 15, 2010 7:14 AM , Blogger Joe Friel said...

Josh--Once in good aerobic condition they are easy.

At March 15, 2010 2:12 PM , Blogger Justin said...

Wow, you could do 100% for an olympic and still run a good 10K after it? I thought FPT was the highest watts you could hold for one hour. Just curious cause I really like training with power, just want to make sure that I am racing correctly with it!

At March 15, 2010 2:22 PM , Anonymous Roland said...

Hi Joe,
thanks for this post. Working with your mountainbikers bible for three years now.
I've done a lactate test in a studio some days ago. And there is a lot of confusion, because the results are about 6 to 9 beats low compared to the time trial tests I did over the last two years. So I'm to sure where to set my training zones.
Maybe something has been wrong with the test setup or the interpretation of the results.
It would be great, if could post something about the essentials for correct lactate testing.

At March 15, 2010 2:28 PM , Anonymous Roland said...

Hi Joe,
thanks for this post. I'm working with your mountainbikers bible for three years now.
I have done a lactate test in a studio some days ago. And there is a lot of confusion now, because the results a about 6 to 9 beats low compared to the time trial test I did over the last two years. So I'm really not sure where to set my training zones.
Maybe something has been wrong with the testsetup or with the interpretation of the results.
Would be great, if you could post something about the essentials of correct lactate testing.

At March 15, 2010 6:28 PM , Blogger Joe Friel said...

Justin--Well, like I said, from sprint to Oly.

At March 16, 2010 11:29 AM , Blogger Marty said...

Hey Joe,
thanks for the great info, as always. I'm curious how this relates to racing Super D, which will be my primary mtb discipline this summer. Super D feels like a prolonged sprint, at a HR that seems a bit higher than LT. Talk about lactic acid burning! Is improving my LT HR enough to train for this, or do I need to also focus on shorter, harder efforts? Thanks so much.

At March 16, 2010 12:04 PM , Blogger Joe Friel said...

Marty--You need both.

At March 17, 2010 6:56 AM , Blogger HEATH said...


To make sure I get it....regarding "tolerance" or ability to "remove" lactic acid:

Training at LT or above is "tolerance" training. Your post explains this.

Training at long duration uses up glucose in muscles which helps ability to "remove" lactic acid utilizing some as fuel.

Did i get it right?


At March 17, 2010 12:21 PM , Blogger Pieter said...

just wondering...

FTP=the power one can hold for an hour.
LTHR = the HR of hartrate one can hold for an hour.

Does that mean that FTP and LTHR do correspond : when riding during 'a longer time' at LTHR one rides at his FTP ?

Is this not a much easier way to put a number on FTP than one hour "all out", or 20 minutes "all out", and then -x% to determine the FTP ?
It seems als to me that doing a test of one hour "all out" does not fit in a base period ?

just wondering...

(by the way, thanks for your books, thanks for this blog, the genius of your writing is that it's comprensible for a non-professionnal...)

At March 17, 2010 4:08 PM , Blogger Joe Friel said...

heath--Best way to train body to remove lactate is to also train at or above LT.

At March 18, 2010 1:32 PM , Anonymous DS said...

Joe - you formerly determined lactate threshold heart rate by using the average heart rate for the last 20 minutes of a 30-minute maximum-effort run. Why the change, and will the result differ? (I've got no 1-hour races on the horizon, and I'm trying to avoid the max-effort 1-hour run.)

At March 19, 2010 5:29 AM , Blogger Joe Friel said...

DS--I had hoped to stay away from this issue as it's a bit complex. I've discussed in some detail some place here before. Bottom line is.. if you don't have a 1 hr race available do a 30 min TT workout (solo) to find LTHR and FTP. Has to do with intensity and motivation in a race vs a workout.

At March 21, 2010 8:20 AM , Blogger Rayomand said...

Hi Joe, At outset thanks for sharing such gr8 post / knoweldge. I have an issue with Leg Cramps when i carry out 30 min LTHR cycle test especially in last few minutes (i do these after 2 hrs of Zone 2 workout) The same is true when i do long Tempo Efforts in zone 3 ~4. This doesnt happen when i train in zone 2 even for 4 ~ 5hrs. These cramps is hampering my peformance to push my system further. Any Suggetions on this? I am following the Cycling Training Bible. Thanks

At March 21, 2010 9:27 AM , Blogger Joe Friel said...

Rayomand--Go here - - scroll down to Muscle Cramping and read. Good luck.

At March 22, 2010 6:35 AM , Blogger Celso said...

Joe, excellent article as always. Could you say something about adapting the body to burn more fat instead of glycogen to reduce lactic acid effects and if weight lifting has any effect on tolerance?

At March 24, 2010 8:16 PM , Anonymous Ed said...

Could you elaborate on your reply to Josh, "-Once in good aerobic condition they are easy?" Does that mean that RPE isn't good for setting the workout intensity when doing AeT, that the RPE at AeT will change as fitness improves? Or are you saying that, warmed up, RPE will feel the same at the start of the ride, even as fitness develops, but when unfit, the RPE is going to go up up up as the ride proceeds that day even though the power is staying the same?

At April 6, 2010 2:23 PM , Blogger birly-shirly said...

Joe - great work, as ever.

Using the procedures in your Tri Bible, I've worked hard in the last few months on aerobic base building - to the point where I meet the <5% HR decoupling test.

I've also, using your 30min solo workout protocol, determined a LTHR of 189/190. This is the consistent result of 2 separate tests, 6 weeks apart. The max HR I've seen running is 198.

This seems high to me. Within the 80 - 85% range that you give, but all false modesty aside, I don't feel that fit yet. I know I could lose some weight (work in progress, but currently around 20% BF), but I'm mid-thirties and LTPace is 7min 30 sec per mile.

I thought, broadly speaking, that the "goal" of extensive endurance was coupling of HR and pace at lower intensity, and that tempo training would push up LTHR - but much of that work seems to have been done now, and I'm still SLOW!

Any thoughts on whether, given these results, I'll benefit from continuing with a mix of Z2 and tempo work and hope for gains in economy - or is it time to up the intensity?

At April 6, 2010 2:50 PM , Blogger Joe Friel said...

birly-shirly--You're not training to change LTHR. It's pretty stable once you are even moderatly fit. Your goal is to lift output (power, pace). There are no awards given at races for the highest LTHR.


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