Respiratory Rate as a measure of the Lactate Threshold

Hi
Just getting into this whole physiology with cycling thing in regards to training. Went out training today with the HR monitor for the third time today and noticed that at around 180ish BPM my respiratory rate increased exponentially. Now 180ish or thereabouts corresponds quite closely to what my lactate threshold is. My question is, is this increase in respiratory rate an accurate measure of when lactate threshold is reached? I seemed to quite easily be able to keep a normal resp rate when riding at 150 but at 180 i was hyperventilating to the max.
Thanks
Jon

Yes and no.

First, Lactate threshold is a accurate concept, that is rather vague in its day to day application.

Most people on this site refer to LT as being the point where lactate curve starts to rise above the normal level. In theory, you can hold that level for.. I don't know, probably 45 to 75 minutes, depending on the fitness level. Could be more, could be less. Well prepared and tapered, one can hold LT power for longer than that.

And one can stand even higher levels of blood lactate. Some call that anaerobic threshold, or onset of blood lactate accumulation or whatever. So I think of lactate threshold as being a large zone, maximal sustained power for durations between 15 and 90 minutes.

Ventilatory Threshold (breathing regulary but not heavily) and respiratory compensation point probably (breathing more heavily) occurs somewhere in (or slightly below in the case of VT) that range. But where exactly? I think the correlation is too weak to pinpoint exactly where it occurs. It probably varies from rider to rider, and from time to time.

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!!!

Try this link
http://www.cyclingforums.com/showthr...=1#post2498133

Probably not, but more importantly, it is the number that Carmichael's system is built around, so if you're applying his zones and workout structure, that's the number you should use.

Mostly, you'll get faster. If you're really out of shape right now, your HR@LT may rise (mine did over the first couple years of training), but mostly it's the power you can produce at any specific level of exertion that goes up.

Really, it depends on the length of the time trial, and your definition of LT (do a search for lactate threshold and posts by Ric - he discusses a couple of definitions). Short time trials, you'll be over LT. I've seen some discussions that LT is actually a low enough power output that you'd be over it for any TT an amature is likely to compete in - see Solar's post.

Frankly I think the notion that you'd time trial at your HR@LT comes from using time trials to determine a proxy for HR@LT.

LT can be defined as either the HR, and/or Power Output at which Lactate begins to accumulate, as both these parameters correlate very well at any given training level for any individual. As fitness inproves, so to does the LT, but it is always defined in this manner. The range between LT and maximum lactate levels is not actually the same thing, as it is physically possible to produce more lactate, by working harder, which is a factor of both psychological will and biochemical and biomechanical factors. Most people can handle only so much lactate before they pull out. Ventilatory Threshold has been shown to correlate with LT, but there is nearly as much evidence to suggest it is coincidental and that there is no true relationship between them. I have two articles I found in my stash which are specific to this exact topic and will post details once i have read them. The title is on this thread http://www.cyclingforums.com/showthr...15#post2545315

PS. Danch is correct that amateurs have a relatively low LT and you would pretty much always be training above it, that is part of why amateurs show massive improvements very quickly cf pro's. It's a percentage thing. To illustrate, 1 Year to a five year old is 20% of their life, but to a fifty year old it is only 2%. thats why time seems to go so fast as we get older i guess!

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B. Exercise Science.