Ask the Expert: Lactate Threshold Resources Needed

ICA member Cheryl has an interesting situation with some riders in her classes questioning her use of LT-based heart-rate zones and moving away from the maximum heart-rate zone protocol. She sent me this inquiry:

Hi Jennifer
I wanted to ask if there is specific scientific evidence that concludes that lactate threshold is a better indicator of fitness and therefore better used in spin classes rather than max heart rate. I have doctors in my classes as well as other research types that are not sold on this new way of thinking and therefore not sold on the concept. Scientific studies or whatever you base your discussions on lactate threshold

She also clarified that among her students is a gastro doctor and a few scientific-type folks who ask for references for everything she presents to them.

This is an interesting conundrum because doctors are supposed to know it all, right? Or are they? I’ve had this discussion with many of my fellow trainers, and even some doctors and medical students I know. The consensus is that (most) doctors treat illness, and most of them specialize in one aspect of illness. Many have little education in wellness, fitness, and training unless they happen to be into athletic training for themselves or are athletic doctors. 

But who is going to tell a doctor they are wrong? They may not take kindly to that! The public tends to believe every word that someone with an “M.D.” after their name tells them, even if it has nothing to do with what that doctor specializes in. I would venture to say that even some cardiologists do not know that much about fitness. They work with diseased hearts, not necessarily how to prevent disease through cardiovascular conditioning.

(On the other hand, when it comes to doctor’s orders for medical issues in their specialty or medicines to take or avoid, always defer to them.)

Are you faced with these types of questions from students, challenging your sources or your efforts to move beyond old training knowledge to more current techniques? Do you want to increase your own understanding of heart rate training? If so, are you ready for some heavy reading material? It’s important to educate yourself as much as possible so you can support your stance with research like Cheryl is doing. You can blame it on what you learned from the Indoor Cycling Association, but I also want to give you as much background information as possible so you know where these sources are coming from. Spend some time going over the resources below—you may need to print these out and read them over the next few months. You will emerge with a lot more answers about lactate threshold and why maximum heart rate equations and zones are (or should be) a thing of the past.

Our knowledge of exercise science is constantly expanding; as we gain insight into exercise metabolism, some long-held beliefs are often challenged. I always defer to what top cycling and endurance coaches are doing; they react much faster than the fitness industry to changes in understanding about how the body responds to exercise and training. They can’t be caught using dated coaching techniques because their athletes will no longer be as competitive. By accessing and paying close attention to this huge body of training knowledge that is available to us via these coaches, educated cycling instructors will stay ahead of the pack and ahead of the trends. They will also avoid useless trends. As a result, we will dump outdated training methods much faster than the rest of the industry and in the process, help our students reach their fitness goals faster. Maximum heart rate training zones are one of these useless trends.

Note I didn’t say heart rate training is useless—it is still an extremely viable and important look into our body’s response to the training we put it through. But you shouldn’t be prescribing exercise based on maximum heart rate, especially one based on age.

There are no endurance coaches worth their salt that are using maximum heart rate training zones anymore. The fitness industry, however, is incredibly stubborn and does not change quickly. Max HR equations were debunked years ago, but they are still embedded into most cardio equipment and every HR monitor that is targeted at the general fitness community.

The fitness industry prefers simplicity and expediency over accuracy. A maximum heart rate equation based on age is the epitome of simple…but it is not only not accurate, but your “maximum” heart rate is also physiologically not that important. It’s not an intensity where you should train, and the other levels of effort are not relative to your theoretical maximum. Your lactate threshold heart rate, on the other hand, is what is important as it relates to effort and performance.

Unfortunately, using lactate threshold to determine training zones isn’t a simple equation–it involves hard work and paying attention to your body’s reaction to the work. The most accurate method is to have it measured through blood lactate tests or VO2 max tests where LT is calculated based on gas exchange. These can be expensive and aren’t accessible to a large number of people.

An alternate way to estimate LT and subsequent training zones is by doing a field test, such as a 30-minute time trial. These can be quite challenging so they are not accessible to all participants. Another way is to perform a Talk Test to estimate the ventilatory threshold (VT) which correlates well with LT. Dr. Carl Foster of the University of Wisconsin is the lead researcher and developer of the Talk Test to estimate VT/LT.

Below is a list of resources on the following subjects: why MHR is not accurate or reliable, what is lactate threshold, how to determine LT and LTHR training zones; and what is the Talk Test and ventilatory threshold (VT).

That’s probably enough ammunition for you for a while! Let me know if you have any additional questions on this topic.

Happy reading!


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