Heart Rate @ Lactate Threshold

Hello,

My name is Scott and I'm new to this forum and cycling for that matter. I just bought a trek 2100 in August. I have a few questions and I was wondering if anyone out there could answer them for me.

First, what is the correct way of determining one's Lactate Threshold? I've tried the Chris Charmichael method by doing two 8 miniute time trials and averaging my heart rate. I came up with the number 176. Is that my LT?

Next question. When working on improving one's LT, what improves? Does one's heart rate @ Lactate Threshold stay the same for there whole life or does the distance improve during the 8 miniute time trial. For example, say at the begining of April I do a 8 miniute time trial and when eight miniutes is up I cover 3 miles. Then at the begining of May I do the same 8 miniute time trial and cover 3.5 miles. What changes? My heart rate @ Lactate threshold or my speed and distance covered.

Last question. When doing a time trial, where should my heart rate be in relation to my Lactate Threshold? I've read somewhere that my time trialing heart rate should be just below or right at my Lactate threshold. Is that true?.............Please someone out there, please help me answer these questions. You can also e-mail me. brewcityfirekid@hotmail.com
Thank you so much!!!

Hi, Scott. Welcome.

The only correct way of determining LT is through blood testing while cycling in a lab. Since LT dictates one's sustainable effort level, other less intensive methods have been developed help estimate that sustainable effort level in terms of HR, power, or speed. An athlete can typically exercise at LT for ~3hrs, so an 8-min TT HR would need to have some correction factors applied to it before it gave a good indication of HR @ LT.


As I said, LT is a certain exercise intensity. What improves through training is *power* @ LT, *speed* @ LT, etc. In other words, your body is able to produce more output while producing the same lactate as before. It's possible that HR @ LT would be lower if your stroke volume had increased, but understand that HR is an indication of exercise intensity (like lactate), not a cycling output.

LT can typically be sustained for ~3hrs, so for most TT's your HR will be much higher than your HR @ LT. Additionally, it depends on the TT distance, as a 10K pace would be higher than, say, a 40K TT pace. If I'm not mistaken, HR @ LT would be in the upper 70's or lower 80's as a % of Max HR, whereas a 10K TT pace would be 90+% easy. Hope that helps.

IIRC, FT is typically ~10% higher than LT, at least in power terms. I'm not sure about the HR difference.

Right, and a 10K TT would be done at ~5-10% higher than FT, power-wise.

Believe there could be some confusion on the term LT. Seems to me the OP is using LT to mean the OBLA or MLSS intensity level which is measured on a lab test ~4 mmol/ml blood lactate, instead of the (much lower) level where blood lactate first rises 0.5 or 1 mmol/ml above resting levels.

I'm curious. Why do you care what your LT is? The reason I ask is that I, for example, do not know what my LT is, have never known what my LT is, and will in all likelihood never know what my LT is (other than deriving it as a function of my FT). The reason I don't care is that it has nothing to do with how I train or race or measure my fitness or my progress. So, I'm curious. Why do you want to know?

I wouldn't doubt it, based on how loosely the terms are thrown around in training articles, videos, and books. Good clarification, in any case.

Is there a good, round figure for how long a typical rider can continue at OBLA?

If you take OBLA as a fixed concentration of 4mmol / L then it varies among individuals. A nice paper on the whole thing is this one:

http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=9710868

BL.

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The heart rate you are at when you reach your LT is the point where you go from aerobic exercise to anaerobic exercise. Aerobic exercise burns fat, anaerobic does not. If you want to loose weight you train below your LT for long periods of time to burn fat, if you want to have extremely high speeds in sprints, then you train at or above your LT for a shorter amount of time.

Its pretty much just another thing to help you maximize the effect of your training.

I realize there are many training schemas out there, but I use Andy C's schema and not one of the training levels requires knowledge of LT. So, it sounds like one of those things that may be nice to know, but I have no idea what I would do with that knowledge.

This is untrue. You are always producing energy aerobically. unlesss you mean the point where some work begins to be produced anaerobically. That may be around OBLA or MLSS, but no LT. And still, it's a very small % of the energy contribution until you get to ~10 minutes.

Fergie-you out there? I recall you saying something about 100 meter dashes being 10% aerobic? Can you add anything?

What does OBLA and MLSS stand for?

Onset of blood lactate accumulation. And Maximal Lactate Steady State, if I am not mistaken.

You see, ToffoIsMe, lactate threshold is a concept that everyone understand, but many have their own variation, or interpretation.

Here, on this site, many members seem to agree in splitting that zone in two : Lactate Threshold being the point at which, lactate starts to accumulate over the normal level. MLSS or OBLA is interpreted as being the point just before Lactate curve grow out of control, so to speak.

I did not know that running 100 hurdle involved 10% aerobic file, I thought it would be a bit lower, but just a bit. Running a marathon, or cycling a century, involves mostly aerobic file, but it also involves some anaerobic. There is no white, no black, just shades of gray.

Studies using the Cosmed K2 equipment are starting to shed new light on the contribution of energy to various types of exercise. Early days yet.

Hamish Ferguson
Cycling Coach

This is one thing that annoys me about this forum. He asks a simple HR related question and get a bunch of power related answers. If he wanted to know about POWER he would have posted it in the "Power Training" forum.

According to Carmichael your LT is 92-95% of your field test average HR (Actually a 3 mile out and back).

FYI - not everyone has a power meter.