View Full Version : Lactate Threshold

01-05-2008, 04:46 PM
I did my 2nd Spinervals workout today with the new trainer, this time the focus was "building the aerobic base". They say to keep your heartrate about 10 b.p.m. below your lactate threshold. Well, I have no idea what my lactate threshold is, and it seems to be a rather complicated measurement. Does anyone here know of an easy-ish way to approximate where one's lactate threshold is? Thanks!

(Incidentally I kept my HR average at about 145-150 for this workout....I hope that was at least ballpark....)

01-05-2008, 05:03 PM
The easiest way to estimate your LT is to do a progressive set. It helps to have a buddy to record things as you go.

Warm-up for 10 minutes, be sure to spin up to a high intensity about 3 times during your warm-up but for only 30 sec.

Then start riding at a gear ratio and cadence (80 to 90 is good) that is comfortable but not easy, something that you know you could maintain over 30 min or more. Every minute move into a harder gear. This is easiest if you start out on your big ring in the front and your sec from biggest ring on the back, then you can just keep dropping into a smaller cog on the back. The key is to maintain your cadence throughout the set. Have your buddy record your heart rate and your rating of perceived exertion at the end of every minute. At some point you will suddenly start breathing a lot faster. This will be a sudden change, not gradual. Have your buddy record your HR at that point. Keep going until you run out of gears or your legs fail. The HR at which your breathing suddenly shifts is a good estimate of LT.

After all is said and done, graph your HR against time and somewhere around the estimated LT you should see a sudden increase in the slope of the graph. This confirms that what you're looking at is the HR at which your primary energy system usage changes and you're starting to go into oxygen debt.

The other way to do it is to estimate your LT based on your max HR. Hopefully you know what your maximum HR is on the bike (actually observed it). Approximately 60 to 65% is an estimate of LT. This formula is completely useless for athletes with a lot of training in their background.

01-05-2008, 05:32 PM
Minor but related thread-jack - Wahine - my friend's husband is a tri coach and he does lactate threshold testing using a computrainer (and blood tests). I was thinking of getting him to test mine so I can train more efficiently. Do you think it's of any value? And if so, what time of year would be best?

01-05-2008, 07:33 PM
Yes. Definitely worth while. Even better if he does VO2 Max testing. But LT testing is great. And the best time to do it is now, at the beginning of a training season after you have a couple of weeks of consistent riding in your legs.

01-05-2008, 11:31 PM
Apart from getting your LT measured in a sports lab, you can work on perceived effort.

Get yourself on a trainer, on a steady hill that challenges you, or on a flat bit of road in a big gear and go as hard as your can.

When you get to the point of your legs aching with a burning sensation you are entering your lactate threshold. When you get to the point of wanting to throw up, you are almost at your max heart rate.

The zone you want to work in to be working in your LT is after the legs start to burn but before you want to throw up.

Here are a few links that talk about LT on bikes - they may have some useful bitys in or prompt questions you could post in this thread as well...

(There is also some discussion about LT when running too but I am not sure where those threads are.)

Heart rate question

Training heart rate zone

Training for Time Trials

How to start training


What is maximum heart rate?

01-10-2008, 05:14 PM
Wahine, RR, thanks for your informative replies! Guess I will try to figure out my lactate threshold and HR max this weekend so that I can train a little more effectively.

01-10-2008, 11:37 PM
Hey there Mal
I'd be interested to hear how your "investigation" goes.

Out of interest, do you know what your resting heart rate is?

And when you are watching the numbers this wekend, see if you can get an estimate on your max heart rate. This will help you work out "zones" for training in.